fix(engine): defend autostash drop against TOCTOU race

dropAutostashBySha resolved SHA→stash@{N} then ran git stash drop ${ref}
non-atomically. Any other process (interactive shell, parallel merger,
fix-agent) pushing a stash between resolve and drop shifted the index, so
we silently dropped the wrong entry while leaving ours behind. The task
log then claimed "Restored pre-merge autostash X cleanly" even though the
stash was still in the list — observed on FN-3558 (e81e922) and others.

Verify the ref still resolves to our SHA via git rev-parse before dropping;
on mismatch, re-resolve and retry up to 5x. Return success/failure so the
caller can record honest status to the task feed instead of unconditionally
logging "cleanly".

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

docs/PLUGIN_AUTHORING.md

@@ -1150,6 +1150,16 @@ Read-only board/task card projection plugin for Even Realities companion flows.
 - Demonstrates: plugin routes protected with API-key auth, store reads via `ctx.taskStore`, and card-deck projection helpers
 - Features: `GET /board/cards`, `GET /board`, and `GET /tasks/:id/cards` endpoints with compact card payloads
 
+### [Even Realities Glasses Plugin](../../plugins/fusion-plugin-even-realities-glasses/)
+
+Task-focused card bridge plugin for Even Realities glasses companion flows.
+
+- Features: quick capture text into new tasks via the plugin route
+- Features: polling-based task transition notifications on configured columns (default `in-review`)
+- Features: agent actions for start work (`in-progress`) and request review (`in-review`), gated by `enableAgentActions`
+- Demonstrates: settings schema for `fusionApiBaseUrl`, `fusionApiToken`, `glassesDeviceId`, `pollingIntervalSeconds`, `notifyOnColumns`, `quickCaptureDefaultColumn`, and `enableAgentActions`
+- Demonstrates FN-3737-aligned display limits: `EVEN_CARD_MAX_CHARS_PER_LINE = 28`, `EVEN_CARD_MAX_LINES_PER_CARD = 8`, `EVEN_CARD_MAX_DECK_SIZE = 12`
+
 ### Installing Example Plugins from Settings
 
 All example plugins can be installed via the dashboard Settings → Plugins UI: