fix: resolve Greptile P1 close() timer leak, engine git init, dashboard test

- store.ts close(): clear retry timer and buffer before nulling _db to
  prevent re-opening a new connection after close (Greptile P1)
- merger-staging-allowlist.test.ts: use `git init -b main` so the
  default branch is always named 'main' regardless of git config
- SettingsModal.test.tsx: fix expected text for compact DroidCli card
  — shows "✓ Active" badge, not "✓ Connected — 1.2.3"

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

packages/core/src/store.ts

@@ -6251,9 +6251,15 @@ ${stepsSection}`;
       } catch (err) {
         // Best-effort flush — entries for deleted tasks will fail FK check.
         // Log the error instead of silently swallowing it.
-        console.warn(`[fusion] Could not flush remaining agent log entries on close (${this.db.path}):`, err);
+        console.warn(`[fusion] Could not flush remaining agent log entries on close:`, err);
       }
     }
+    // Cancel any retry timer armed by a failed flush — the DB is about to close.
+    if (this.agentLogFlushTimer) {
+      clearTimeout(this.agentLogFlushTimer);
+      this.agentLogFlushTimer = null;
+    }
+    this.agentLogBuffer.length = 0;
     if (this._db) {
       this._db.close();
       this._db = null;