feat: agent status dashboard with availability timeline and Gemini quota detection

- Detect Gemini TerminalQuotaError (daily quota) as BUDGET_EXCEEDED, not generic FAILED
- Surface container stderr tail in error so quota/rate-limit classifiers can match it
- Add agent_events table to persist rate-limit start/recovery events across restarts
- Add GET /api/agents/status endpoint returning live agent state + 24h event history
- Stats dashboard: agent status cards, 24h availability timeline, per-run execution table

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

1 files changed, 117 insertions, 0 deletions

diff --git a/web/style.css b/web/style.css
index 7a3eb71..37f3b61 100644
--- a/web/style.css
+++ b/web/style.css
@@ -1550,3 +1550,120 @@ dialog label select:focus {
   width: 80px;
   flex-shrink: 0;
 }
+
+/* ── Execution detail table ─────────────────────────────────────────────── */
+.stats-exec-table-wrap {
+  margin-top: 1rem;
+}
+
+.stats-exec-table {
+  width: 100%;
+  border-collapse: collapse;
+  font-size: 0.8rem;
+}
+
+.stats-exec-table th,
+.stats-exec-table td {
+  padding: 0.35rem 0.5rem;
+  text-align: left;
+  border-bottom: 1px solid var(--border);
+}
+
+.stats-exec-table th {
+  color: var(--text-muted);
+  font-weight: 500;
+}
+
+.stats-exec-name {
+  max-width: 220px;
+  overflow: hidden;
+  text-overflow: ellipsis;
+  white-space: nowrap;
+  display: block;
+}
+
+/* ── Agent Status ───────────────────────────────────────────────────────── */
+.stats-agent-cards {
+  display: flex;
+  gap: 0.75rem;
+  flex-wrap: wrap;
+  margin-bottom: 1.25rem;
+}
+
+.stats-agent-card {
+  display: flex;
+  flex-direction: column;
+  gap: 0.25rem;
+  padding: 0.75rem 1rem;
+  border-radius: 8px;
+  border: 1px solid var(--border);
+  min-width: 160px;
+}
+
+.stats-agent-card.agent-available {
+  border-color: var(--state-completed);
+  background: color-mix(in srgb, var(--state-completed) 8%, transparent);
+}
+
+.stats-agent-card.agent-rate-limited {
+  border-color: var(--state-failed);
+  background: color-mix(in srgb, var(--state-failed) 8%, transparent);
+}
+
+.stats-agent-name {
+  font-weight: 600;
+  font-size: 0.9rem;
+  text-transform: capitalize;
+}
+
+.stats-agent-status {
+  font-size: 0.75rem;
+  color: var(--text-muted);
+}
+
+/* ── Availability Timeline ─────────────────────────────────────────────── */
+.stats-timeline-row {
+  margin-bottom: 0.75rem;
+}
+
+.stats-timeline-label {
+  display: block;
+  font-size: 0.78rem;
+  color: var(--text-muted);
+  margin-bottom: 0.2rem;
+  text-transform: capitalize;
+}
+
+.stats-timeline-track {
+  display: flex;
+  height: 18px;
+  border-radius: 4px;
+  overflow: hidden;
+  background: var(--bg-card);
+  width: 100%;
+}
+
+.stats-timeline-seg {
+  height: 100%;
+  transition: opacity 0.1s;
+}
+
+.stats-timeline-seg:hover {
+  opacity: 0.8;
+}
+
+.seg-available {
+  background: var(--state-completed);
+}
+
+.seg-limited {
+  background: var(--state-failed);
+}
+
+.stats-timeline-timelabels {
+  display: flex;
+  justify-content: space-between;
+  font-size: 0.68rem;
+  color: var(--text-muted);
+  margin-top: 0.15rem;
+}