fix(ds-pill): default show_dot per mode (badges clean, markers keep dot) (#2107)

Closes #2001.

DS::Pill defaulted show_dot: true for both modes, so every status/category
badge got a leading dot by default — redundant with the pill shape + tone +
label already carrying the signal, and noisy in dense lists. More than half
the marker:false callsites were already passing show_dot: false to fight it.

The default is now mode-aware: marker: true keeps the dot (stage markers),
marker: false (badges) is dot-less. An explicit show_dot: still wins.

Only one in-tree callsite relied on the old default without an icon and wants
the dot: settings/providers/_status_pill (live connection state) — pinned with
show_dot: true. The enable_banking "Beta" badge loses its dot, which is the
desired outcome (ref #1997). Icon-bearing transaction badges are unaffected
(an icon already suppresses the dot).

Left the now-redundant show_dot: false overrides in place to avoid churn and
conflicts with in-flight pill-migration branches; they're harmless (explicit
false == new default).

Adds tests pinning the per-mode default resolution; updates the Lookbook
preview to show the opt-in dot vs the clean default.

test/components/previews/pill_component_preview.rb

@@ -39,8 +39,12 @@ class PillComponentPreview < ViewComponent::Preview
   # @!endgroup
 
   # @!group Status badges (marker: false, semantic tones)
+  # Badge mode is dot-less by default — tone + label carry the signal. Opt the
+  # dot back in with show_dot: true only where it's genuinely additive (live /
+  # temporal status, or a single sparse pill). status_active below shows the
+  # opt-in; status_pending / status_archived show the clean default.
   def status_active
-    render DS::Pill.new(label: "Active", tone: :success, marker: false)
+    render DS::Pill.new(label: "Active", tone: :success, marker: false, show_dot: true)
   end
 
   def status_pending