feat(reconciliation): implement deterministic state reconciliation engine and post-commit hook

- Implement ReconciliationEngine in server/src/handlers/reconciliation.rs
- Auto-transition ADRs to implemented, resolve tech debts, and cascade task unblocking
- Ingest git commit events via POST /api/git/commit and scripts/git-reconcile.py post-commit hook
- Add universal pagination, search filtering, and keyboard navigation to dashboard
- Implement non-destructive task TTL expiry sweeper and gate verification
- Implements: ADR-0102, ADR-0103

server/src/lib.rs

@@ -102,10 +102,37 @@ pub async fn ttl_sweeper_worker(state: Arc<MemoryState>) {
             .unwrap_or_default()
             .as_secs();
 
+        let mut expired_tasks = Vec::new();
         state.project.tasks.modify(|tasks| {
-            tasks.retain(|t| t.expires_at.is_none_or(|exp| exp > now));
+            for t in tasks.iter_mut() {
+                if let Some(exp) = t.expires_at {
+                    if exp <= now && t.is_active() {
+                        t.status = "expired".to_string();
+                        t.updated_at = now;
+                        expired_tasks.push(t.id.clone());
+                    }
+                }
+            }
         });
 
+        for tid in expired_tasks {
+            state.record_activity(
+                "task_expired",
+                &format!("Task {} expired due to TTL", tid),
+                Some("expired"),
+            );
+            state.broadcast_task_event(crate::models::TaskEvent {
+                task_id: tid,
+                status: "expired".to_string(),
+                action: Some("ttl_expire".to_string()),
+                result: Some(serde_json::json!({ "status": "expired" })),
+                error: None,
+                timestamp: now,
+                session_id: None,
+                ..Default::default()
+            });
+        }
+
         state.telemetry.handoff_memos.modify(|memos| {
             memos.retain(|m| m.expires_at.is_none_or(|exp| exp > now));
         });