feat(agent): event timeline API, SSE stream, Coolify DDL, env template

- Add agent_session_events table + GET/POST events + SSE stream routes
- Build Agent tab: hydrate from events + EventSource while running
- entrypoint: create agent_sessions + agent_session_events on container start
- .env.example for AGENT_RUNNER_URL, AGENT_RUNNER_SECRET, DATABASE_URL

Made-with: Cursor

scripts/migrate-fs-tables.sql

@@ -93,6 +93,25 @@ CREATE INDEX IF NOT EXISTS agent_sessions_project_idx
 CREATE INDEX IF NOT EXISTS agent_sessions_status_idx
   ON agent_sessions (status);
 
+-- ---------------------------------------------------------------------------
+-- agent_session_events  (append-only timeline for SSE + replay)
+-- ---------------------------------------------------------------------------
+CREATE TABLE IF NOT EXISTS agent_session_events (
+  id              BIGSERIAL PRIMARY KEY,
+  session_id      UUID NOT NULL REFERENCES agent_sessions(id) ON DELETE CASCADE,
+  project_id      TEXT NOT NULL,
+  seq             INT NOT NULL,
+  ts              TIMESTAMPTZ NOT NULL,
+  type            TEXT NOT NULL,
+  payload         JSONB NOT NULL DEFAULT '{}'::jsonb,
+  client_event_id UUID UNIQUE,
+  created_at      TIMESTAMPTZ NOT NULL DEFAULT now(),
+  UNIQUE(session_id, seq)
+);
+
+CREATE INDEX IF NOT EXISTS agent_session_events_session_seq_idx
+  ON agent_session_events (session_id, seq);
+
 -- ---------------------------------------------------------------------------
 -- NextAuth / Prisma tables  (required by PrismaAdapter + strategy:"database")
 -- Only created if not already present from a prisma migrate run.