claude: accepting ExitPlanMode exits plan mode in the panel (T-337)

ExitPlanMode arrives as a can_use_tool permission prompt and was approved
like any other tool — the control_response was sent but the tracked
SessionStatus.permissionMode never changed, so the mode indicator and
composer stayed on "plan" after the plan was accepted.

On approving an ExitPlanMode prompt, sync the tracked mode to 'default'
(the CLI performs the transition itself, so no set_permission_mode control
request is sent — we only mirror it). The change rides the existing
statusStream → claude_pane._status plumbing, so the permission-mode
control and status indicator update with no extra wiring. Deny, and any
non-ExitPlanMode tool, leave the mode untouched.

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

CHANGELOG.md

@@ -16,6 +16,14 @@ heading, and (b) bumping `pubspec.yaml` `version:` in the same commit.
 
 ## [Unreleased]
 
+### Fixed
+
+- **Accepting ExitPlanMode now leaves plan mode in the conversation panel.**
+  Approving Claude's plan (the ExitPlanMode tool) transitioned the underlying
+  session out of plan mode, but clide's tracked permission mode didn't follow,
+  so the mode indicator and composer stayed stuck on "plan". The approval now
+  syncs the tracked mode to `default`. (T-337)
+
 ### Added
 
 - **Double-tap-modifier shortcuts (e.g. double-Shift "Search Everywhere").**