group consecutive same-file edits into one collapsed card (T-296)

A run of 2+ consecutive edits to the same file now folds into one ClideHolderCard
labelled '# edits' (coalesceEditRuns, run after groupConversation) instead of a
stack of cards; a different file or an interleaving step splits the run. Every
edit stays reachable on expand.

The holder gained an optional aggregate status. New owned primitives: ClideSpinner
(the logo mark, monochrome, 3D Y-axis rotation, reduced-motion-aware) and
ClideStatusIndicator (running→spinner / success→check / error→cross, with an
AnimatedSwitcher seam for a richer transition later — kept self-contained, not
built on ConversationCard's mark). The activity card shares the same indicator.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

CHANGELOG.md

@@ -18,6 +18,13 @@ heading, and (b) bumping `pubspec.yaml` `version:` in the same commit.
 
 ### Added
 
+- **Consecutive edits to one file fold into a single card.** A run of edits to
+  the same file now collapses to one `# edits` holder (the latest edit as the
+  ticker; every edit reachable on expand) instead of a stack of cards — a
+  different file or an interleaving step splits the run. The card carries an
+  aggregate live status: a new logo-mark **`ClideSpinner`** while editing,
+  settling to a check (or a cross on failure); the activity card shares it.
+  (T-296)
 - **Collapse toggles in the status bar.** A small caret-line button bookends
   each end of the bottom status bar — left collapses/expands the sidebar, right
   the context pane. The chevron points inward to collapse, outward to expand,