fix(docs): finish bare-relative link conversion + add lint guardrail

Copilot flagged two stragglers on editors.md where the previous
file-by-file conversion stopped halfway. Sweeping for the same
pattern across the active content tree found 76 bare relative
internal links total — 14 in this PR's already-modified files
(Copilot's two plus twelve more) and 62 in unchanged files.

Why the build doesn't catch this
─────────────────────────────────
`onBrokenLinks: 'throw'` (set in this PR) only validates *file-based*
markdown references — links whose URL ends in `.md` / `.mdx`. Those
go through Docusaurus's file resolver, which can prove the target
exists. Bare relative URL paths like `[Foo](../foo)` skip that
resolver entirely; Docusaurus emits them as raw hrefs. The browser
then resolves them against the *current* page URL, and for
trailing-slash routes that almost always lands in the wrong
directory. Page navigates client-side and 404s. The linkinator job
in CI *can* catch these, but it's `continue-on-error: true` so
findings are advisory.

What this commit does
──────────────────────
1. Fix all 76 bare relative internal links across the active docs
   tree by appending `.md` to each one (preserving anchors / query
   strings). All 76 targets resolved to real files; no link
   targets changed, only the form of the reference.

2. Fix the component-page generator. 54 of the 76 bare links lived
   in two auto-generated index files (`components/ui/index.mdx`
   and `components/design-system/index.mdx`). The next regeneration
   would have undone the manual fixes without this. The two
   emission sites in `generate-superset-components.mjs` now emit
   `.md`-suffixed links; comment at the call site explains why.

3. Add `docs/scripts/lint-docs-links.mjs` — fast source-level
   linter that scans `.md`/`.mdx` files under the active content
   trees (skipping `versioned_docs/` snapshots) and fails if it
   finds any markdown link whose URL starts with `./` or `../` and
   does not end in `.md`/`.mdx`. Excludes asset paths (.png,
   .json, etc.) and ignores fenced code blocks. Wired up as
   `yarn lint:docs-links`.

4. Add a `Lint docs links` step to `superset-docs-verify.yml`,
   running before the build step so PRs that introduce the pattern
   fail in seconds rather than at build-time / not at all. Blocking,
   not advisory — exactly the gap linkinator's `continue-on-error`
   leaves open.

Verified
────────
- `yarn lint:docs-links` exits 0 on the cleaned tree
- Re-introducing one bare link makes the linter report the exact
  file:line with the offending URL, exit code 1
- All 76 originally-flagged targets resolved to real `.md` / `.mdx`
  files; only the form of the reference changed

docs/developer_docs/components/design-system/index.mdx

@@ -29,10 +29,10 @@ sidebar_position: 1
 
 ## Components
 
-- [DropdownContainer](./dropdowncontainer)
-- [Flex](./flex)
-- [Grid](./grid)
-- [Layout](./layout)
-- [MetadataBar](./metadatabar)
-- [Space](./space)
-- [Table](./table)
+- [DropdownContainer](./dropdowncontainer.md)
+- [Flex](./flex.md)
+- [Grid](./grid.md)
+- [Layout](./layout.md)
+- [MetadataBar](./metadatabar.md)
+- [Space](./space.md)
+- [Table](./table.md)

docs/developer_docs/components/index.mdx

@@ -62,7 +62,7 @@ This documentation is auto-generated from Storybook stories. To add or update co
 4. Run `yarn generate:superset-components` in the `docs/` directory
 
 :::info Work in Progress
-This component library is actively being documented. See the [Components TODO](./TODO) page for a list of components awaiting documentation.
+This component library is actively being documented. See the [Components TODO](./TODO.md) page for a list of components awaiting documentation.
 :::
 
 ---

docs/developer_docs/components/ui/index.mdx

@@ -29,49 +29,49 @@ sidebar_position: 1
 
 ## Components
 
-- [AutoComplete](./autocomplete)
-- [Avatar](./avatar)
-- [Badge](./badge)
-- [Breadcrumb](./breadcrumb)
-- [Button](./button)
-- [ButtonGroup](./buttongroup)
-- [CachedLabel](./cachedlabel)
-- [Card](./card)
-- [Checkbox](./checkbox)
-- [Collapse](./collapse)
-- [DatePicker](./datepicker)
-- [Divider](./divider)
-- [EditableTitle](./editabletitle)
-- [EmptyState](./emptystate)
-- [FaveStar](./favestar)
-- [IconButton](./iconbutton)
-- [Icons](./icons)
-- [IconTooltip](./icontooltip)
-- [InfoTooltip](./infotooltip)
-- [Input](./input)
-- [Label](./label)
-- [List](./list)
-- [ListViewCard](./listviewcard)
-- [Loading](./loading)
-- [Menu](./menu)
-- [Modal](./modal)
-- [ModalTrigger](./modaltrigger)
-- [Popover](./popover)
-- [ProgressBar](./progressbar)
-- [Radio](./radio)
-- [SafeMarkdown](./safemarkdown)
-- [Select](./select)
-- [Skeleton](./skeleton)
-- [Slider](./slider)
-- [Steps](./steps)
-- [Switch](./switch)
-- [TableCollection](./tablecollection)
-- [TableView](./tableview)
-- [Tabs](./tabs)
-- [Timer](./timer)
-- [Tooltip](./tooltip)
-- [Tree](./tree)
-- [TreeSelect](./treeselect)
-- [Typography](./typography)
-- [UnsavedChangesModal](./unsavedchangesmodal)
-- [Upload](./upload)
+- [AutoComplete](./autocomplete.md)
+- [Avatar](./avatar.md)
+- [Badge](./badge.md)
+- [Breadcrumb](./breadcrumb.md)
+- [Button](./button.md)
+- [ButtonGroup](./buttongroup.md)
+- [CachedLabel](./cachedlabel.md)
+- [Card](./card.md)
+- [Checkbox](./checkbox.md)
+- [Collapse](./collapse.md)
+- [DatePicker](./datepicker.md)
+- [Divider](./divider.md)
+- [EditableTitle](./editabletitle.md)
+- [EmptyState](./emptystate.md)
+- [FaveStar](./favestar.md)
+- [IconButton](./iconbutton.md)
+- [Icons](./icons.md)
+- [IconTooltip](./icontooltip.md)
+- [InfoTooltip](./infotooltip.md)
+- [Input](./input.md)
+- [Label](./label.md)
+- [List](./list.md)
+- [ListViewCard](./listviewcard.md)
+- [Loading](./loading.md)
+- [Menu](./menu.md)
+- [Modal](./modal.md)
+- [ModalTrigger](./modaltrigger.md)
+- [Popover](./popover.md)
+- [ProgressBar](./progressbar.md)
+- [Radio](./radio.md)
+- [SafeMarkdown](./safemarkdown.md)
+- [Select](./select.md)
+- [Skeleton](./skeleton.md)
+- [Slider](./slider.md)
+- [Steps](./steps.md)
+- [Switch](./switch.md)
+- [TableCollection](./tablecollection.md)
+- [TableView](./tableview.md)
+- [Tabs](./tabs.md)
+- [Timer](./timer.md)
+- [Tooltip](./tooltip.md)
+- [Tree](./tree.md)
+- [TreeSelect](./treeselect.md)
+- [Typography](./typography.md)
+- [UnsavedChangesModal](./unsavedchangesmodal.md)
+- [Upload](./upload.md)

docs/developer_docs/contributing/code-review.md

@@ -327,9 +327,9 @@ stats.sort_stats('cumulative').print_stats(10)
 ## Resources
 
 ### Internal
-- [Coding Guidelines](../guidelines/design-guidelines)
-- [Testing Guide](../testing/overview)
-- [Extension Architecture](../extensions/architecture)
+- [Coding Guidelines](../guidelines/design-guidelines.md)
+- [Testing Guide](../testing/overview.md)
+- [Extension Architecture](../extensions/architecture.md)
 
 ### External
 - [Google's Code Review Guide](https://google.github.io/eng-practices/review/)

docs/developer_docs/contributing/development-setup.md

@@ -668,7 +668,7 @@ A series of checks will now run when you make a git commit.
 
 ## Linting
 
-See [how tos](./howtos#linting)
+See [how tos](./howtos.md#linting)
 
 ## GitHub Actions and `act`
 

docs/developer_docs/contributing/guidelines.md

@@ -77,7 +77,7 @@ Finally, never submit a PR that will put master branch in broken state. If the P
     in `requirements.txt` pinned to a specific version which ensures that the application
     build is deterministic.
   - For TypeScript/JavaScript, include new libraries in `package.json`
-- **Tests:** The pull request should include tests, either as doctests, unit tests, or both. Make sure to resolve all errors and test failures. See [Testing](./howtos#testing) for how to run tests.
+- **Tests:** The pull request should include tests, either as doctests, unit tests, or both. Make sure to resolve all errors and test failures. See [Testing](./howtos.md#testing) for how to run tests.
 - **Documentation:** If the pull request adds functionality, the docs should be updated as part of the same PR.
 - **CI:** Reviewers will not review the code until all CI tests are passed. Sometimes there can be flaky tests. You can close and open PR to re-run CI test. Please report if the issue persists. After the CI fix has been deployed to `master`, please rebase your PR.
 - **Code coverage:** Please ensure that code coverage does not decrease.

docs/developer_docs/contributing/howtos.md

@@ -282,7 +282,7 @@ You can now launch your VSCode debugger with the same config as above. VSCode wi
 
 ### Storybook
 
-See the dedicated [Storybook documentation](../testing/storybook) for information on running Storybook locally and adding new stories.
+See the dedicated [Storybook documentation](../testing/storybook.md) for information on running Storybook locally and adding new stories.
 
 ## Contributing Translations
 

docs/developer_docs/contributing/overview.md

@@ -94,7 +94,7 @@ Look through the GitHub issues. Issues tagged with
 Superset could always use better documentation,
 whether as part of the official Superset docs,
 in docstrings, `docs/*.rst` or even on the web as blog posts or
-articles. See [Documentation](./howtos#contributing-to-documentation) for more details.
+articles. See [Documentation](./howtos.md#contributing-to-documentation) for more details.
 
 ### Add Translations
 
@@ -103,7 +103,7 @@ text strings from Superset's UI. You can jump into the existing
 language dictionaries at
 `superset/translations/<language_code>/LC_MESSAGES/messages.po`, or
 even create a dictionary for a new language altogether.
-See [Translating](./howtos#contributing-translations) for more details.
+See [Translating](./howtos.md#contributing-translations) for more details.
 
 ### Ask Questions
 

docs/developer_docs/contributing/submitting-pr.md

@@ -35,7 +35,7 @@ Learn how to create and submit high-quality pull requests to Apache Superset.
 - [ ] You've found or created an issue to work on
 
 ### PR Readiness Checklist
-- [ ] Code follows [coding guidelines](../guidelines/design-guidelines)
+- [ ] Code follows [coding guidelines](../guidelines/design-guidelines.md)
 - [ ] Tests are passing locally
 - [ ] Linting passes (`pre-commit run --all-files`)
 - [ ] Documentation is updated if needed

docs/developer_docs/extensions/contribution-types.md

@@ -110,7 +110,7 @@ editors.registerEditor(
 );
 ```
 
-See [Editors Extension Point](./extension-points/editors) for implementation details.
+See [Editors Extension Point](./extension-points/editors.md) for implementation details.
 
 ## Backend
 

docs/developer_docs/extensions/extension-points/editors.md

@@ -218,5 +218,5 @@ const disposable = handle.registerCompletionProvider(provider);
 ## Next Steps
 
 - **[SQL Lab Extension Points](./sqllab.md)** - Learn about other SQL Lab customizations
-- **[Contribution Types](../contribution-types)** - Explore other contribution types
-- **[Development](../development)** - Set up your development environment
+- **[Contribution Types](../contribution-types.md)** - Explore other contribution types
+- **[Development](../development.md)** - Set up your development environment

docs/developer_docs/extensions/extension-points/sqllab.md

@@ -157,6 +157,6 @@ menus.registerMenuItem(
 
 ## Next Steps
 
-- **[Contribution Types](../contribution-types)** - Learn about other contribution types (commands, menus)
-- **[Development](../development)** - Set up your development environment
-- **[Quick Start](../quick-start)** - Build a complete extension
+- **[Contribution Types](../contribution-types.md)** - Learn about other contribution types (commands, menus)
+- **[Development](../development.md)** - Set up your development environment
+- **[Quick Start](../quick-start.md)** - Build a complete extension

docs/developer_docs/extensions/quick-start.md

@@ -225,7 +225,7 @@ The `@apache-superset/core` package must be listed in both `peerDependencies` (t
 
 The webpack configuration requires specific settings for Module Federation. Key settings include `externalsType: "window"` and `externals` to map `@apache-superset/core` to `window.superset` at runtime, `import: false` for shared modules to use the host's React instead of bundling a separate copy, and `remoteEntry.[contenthash].js` for cache busting.
 
-**Convention**: Superset always loads extensions by requesting the `./index` module from the Module Federation container. The `exposes` entry must be exactly `'./index': './src/index.tsx'` — do not rename or add additional entries. All API registrations must be reachable from that file. See [Architecture](./architecture#module-federation) for a full explanation.
+**Convention**: Superset always loads extensions by requesting the `./index` module from the Module Federation container. The `exposes` entry must be exactly `'./index': './src/index.tsx'` — do not rename or add additional entries. All API registrations must be reachable from that file. See [Architecture](./architecture.md#module-federation) for a full explanation.
 
 ```javascript
 const path = require('path');

docs/developer_docs/guidelines/backend-style-guidelines.md

@@ -114,7 +114,7 @@ class CreateDashboardCommand(BaseCommand):
 
 ### Data Access Objects (DAOs)
 
-See: [DAO Style Guidelines and Best Practices](./backend/dao-style-guidelines)
+See: [DAO Style Guidelines and Best Practices](./backend/dao-style-guidelines.md)
 
 ## Testing
 

docs/developer_docs/guidelines/frontend-style-guidelines.md

@@ -29,16 +29,16 @@ This is a list of statements that describe how we do frontend development in Sup
 - We develop using TypeScript.
   - See: [SIP-36](https://github.com/apache/superset/issues/9101)
 - We use React for building components, and Redux to manage app/global state.
-  - See: [Component Style Guidelines and Best Practices](./frontend/component-style-guidelines)
+  - See: [Component Style Guidelines and Best Practices](./frontend/component-style-guidelines.md)
 - We prefer functional components to class components and use hooks for local component state.
 - We use [Ant Design](https://ant.design/) components from our component library whenever possible, only building our own custom components when it's required.
   - See: [SIP-48](https://github.com/apache/superset/issues/11283)
 - We use [@emotion](https://emotion.sh/docs/introduction) to provide styling for our components, co-locating styling within component files.
   - See: [SIP-37](https://github.com/apache/superset/issues/9145)
-  - See: [Emotion Styling Guidelines and Best Practices](./frontend/emotion-styling-guidelines)
+  - See: [Emotion Styling Guidelines and Best Practices](./frontend/emotion-styling-guidelines.md)
 - We use Jest for unit tests, React Testing Library for component tests, and Cypress for end-to-end tests.
   - See: [SIP-56](https://github.com/apache/superset/issues/11830)
-  - See: [Testing Guidelines and Best Practices](../testing/testing-guidelines)
+  - See: [Testing Guidelines and Best Practices](../testing/testing-guidelines.md)
 - We add tests for every new component or file added to the frontend.
 - We organize our repo so similar files live near each other, and tests are co-located with the files they test.
   - See: [SIP-61](https://github.com/apache/superset/issues/12098)
@@ -46,6 +46,6 @@ This is a list of statements that describe how we do frontend development in Sup
 - We use OXC (oxlint) and Prettier to automatically fix lint errors and format the code.
   - We do not debate code formatting style in PRs, instead relying on automated tooling to enforce it.
   - If there's not a linting rule, we don't have a rule!
-  - See: [Linting How-Tos](../contributing/howtos#typescript--javascript)
+  - See: [Linting How-Tos](../contributing/howtos.md#typescript--javascript)
 - We use [React Storybook](https://storybook.js.org/) to help preview/test and stabilize our components
   - A public Storybook with components from the `master` branch is available [here](https://apache-superset.github.io/superset-ui/?path=/story/*)

docs/developer_docs/guidelines/frontend/component-style-guidelines.md

@@ -53,7 +53,7 @@ superset-frontend/src/components
 
 **Storybook:** Components should come with a storybook file whenever applicable, with the following naming convention `\{ComponentName\}.stories.tsx`. More details about Storybook below
 
-**Unit and end-to-end tests:** All components should come with unit tests using Jest and React Testing Library. The file name should follow this naming convention `\{ComponentName\}.test.tsx`. Read the [Testing Guidelines and Best Practices](../../testing/testing-guidelines) for more details
+**Unit and end-to-end tests:** All components should come with unit tests using Jest and React Testing Library. The file name should follow this naming convention `\{ComponentName\}.test.tsx`. Read the [Testing Guidelines and Best Practices](../../testing/testing-guidelines.md) for more details
 
 **Reference naming:** Use `PascalCase` for React components and `camelCase` for component instances