Harden SimpleFIN sync: protect user data, fix stuck syncs, optimize API calls (#671)

* Implement entry protection flags for sync overwrites

- Added `user_modified` and `import_locked` flags to `entries` table to prevent provider sync from overwriting user-edited and imported data.
- Introduced backfill migration to mark existing entries based on conditions.
- Enhanced sync and processing logic to respect protection flags, track skipped entries, and log detailed stats.
- Updated UI to display skipped/protected entries and reasons in sync summaries.

* Localize error details summary text and adjust `sync_account_later` method placement

* Restored schema.rb

---------

Co-authored-by: luckyPipewrench <luckypipewrench@proton.me>

app/controllers/transactions_controller.rb

@@ -93,9 +93,10 @@ class TransactionsController < ApplicationController
         }
       end
 
-      @entry.sync_account_later
       @entry.lock_saved_attributes!
+      @entry.mark_user_modified!
       @entry.transaction.lock_attr!(:tag_ids) if @entry.transaction.tags.any?
+      @entry.sync_account_later
 
       respond_to do |format|
         format.html { redirect_back_or_to account_path(@entry.account), notice: "Transaction updated" }