feat: add lab SQLite migrate, LiteLLM env, and OTEL/Grafana stack

Enable local workshop readiness with executable SQLite migrations, OpenTelemetry hello signals, and a provisioned Grafana demo dashboard over Tempo/Loki/Prometheus.

Co-authored-by: Cursor <cursoragent@cursor.com>

migrations/001_tickets.sql

@@ -0,0 +1,27 @@
+-- TicketLab initial schema (lab / walking skeleton)
+CREATE TABLE IF NOT EXISTS schema_migrations (
+  id TEXT PRIMARY KEY NOT NULL,
+  applied_at TEXT NOT NULL
+);
+
+CREATE TABLE IF NOT EXISTS tickets (
+  id TEXT PRIMARY KEY NOT NULL,
+  description TEXT NOT NULL,
+  status TEXT NOT NULL CHECK (status IN ('PENDING', 'CLASSIFIED', 'FAILED')),
+  category TEXT CHECK (
+    category IS NULL
+    OR category IN ('INCIDENT', 'ACCESS_REQUEST', 'BILLING', 'FEATURE_REQUEST', 'OTHER')
+  ),
+  confidence REAL CHECK (
+    confidence IS NULL OR (confidence >= 0 AND confidence <= 1)
+  ),
+  failure_reason TEXT CHECK (
+    failure_reason IS NULL
+    OR failure_reason IN ('AI_TIMEOUT', 'AI_UNAVAILABLE', 'AI_INVALID_RESPONSE')
+  ),
+  created_at TEXT NOT NULL,
+  updated_at TEXT NOT NULL
+);
+
+CREATE INDEX IF NOT EXISTS idx_tickets_status ON tickets (status);
+CREATE INDEX IF NOT EXISTS idx_tickets_created_at ON tickets (created_at);