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/api/rest.rs

@@ -36,6 +36,10 @@ pub async fn gate_verify_handler(
     State(app_state): State<Arc<AppState>>,
     Query(q): Query<GateVerifyReq>,
 ) -> Result<impl IntoResponse, AppError> {
+    let now = std::time::SystemTime::now()
+        .duration_since(std::time::UNIX_EPOCH)
+        .unwrap_or_default()
+        .as_secs();
     let mut found = None;
     let mut to_remove = None;
     app_state.handler.state.env.gates.modify(|gates| {
@@ -44,6 +48,7 @@ pub async fn gate_verify_handler(
                 && g.target == q.target
                 && g.namespace == q.namespace
                 && g.params == q.params
+                && g.expires_at.is_none_or(|exp| exp > now)
         }) {
             found = Some(gates[idx].clone());
             if q.consume {