Phase 7: Bot/extension system

Bot accounts (User rows with is_bot=True), scoped API tokens (read:messages,
write:messages, manage:rooms) authenticated via Authorization: Bearer on both
REST and the WS handshake, live bot WebSocket access on the same /ws/chat
endpoint humans use, message editing (WS "edit" envelope -> message_update
broadcast, fans out cross-instance for free via the existing broadcaster),
incoming webhooks (room-scoped, no auth beyond the URL token), and outgoing
webhooks/event subscriptions (HMAC-SHA256 signed, backgrounded delivery,
creation-time SSRF validation against private/loopback/link-local targets).

Token auth is additive, not a parallel system: a bearer-token-authenticated
bot goes through the exact same room-membership/role checks a session-
authenticated human does everywhere; only read:messages/write:messages are
separately scope-gated (the two message endpoints). manage:rooms scope
enforcement, full per-delivery SSRF re-validation, and bot API rate limiting
were explicitly scoped out (confirmed with the repo owner) as disproportionate
to this phase -- documented as known gaps in backend/README.md rather than
silently skipped.

Admin portal gains a Bots tab (create bots, issue/revoke scoped tokens,
cross-room webhook visibility); RoomInfoPanel gains room-scoped webhook/
subscription management, mirroring how invites already work there. The chat
UI also gets a minimal "edit your own message" affordance -- not asked for
by the issue, but the only practical way to exercise the edit pipeline by
hand instead of only via a scripted bot client.

Along the way: fixed a real bug caught while writing the incoming-webhook
test -- offline-push notification relied on the sender being "connected" to
exclude themselves, true for WS-originated messages but not for the new
webhook path, which has no WS connection for the attributed sender at all.
Now explicitly excluded. Also discovered the REST-only test fixture never
triggered ASGI lifespan, so app.state.broadcaster/presence didn't exist for
it; moved their construction out of the lifespan into create_app() itself
(Redis client construction is synchronous/lazy) so both the WS and
REST-only paths always have them.

New tests/test_bots.py, test_message_edit.py, test_webhooks.py (full suite
now 78/78, stable across repeated runs) plus a scripted end-to-end smoke
test (bot WS join/post/edit, incoming webhook, SSRF rejection, outgoing
delivery) and a full browser walkthrough of the new admin/room UI.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

frontend/src/pages/AdminPage.css

@@ -141,3 +141,90 @@
 .admin-load-more {
   margin-top: var(--sp-4);
 }
+
+.admin-create-form {
+  display: flex;
+  gap: var(--sp-2);
+  margin-bottom: var(--sp-4);
+}
+
+.admin-create-form input {
+  flex: 1;
+  max-width: 280px;
+  background: var(--ds-surface-2);
+  border: 1px solid var(--ds-border);
+  border-radius: var(--radius);
+  padding: 7px 10px;
+  color: var(--ds-text);
+  font-size: 0.84rem;
+}
+
+.admin-bot-detail {
+  background: var(--ds-void-2);
+}
+
+.admin-token-list {
+  display: flex;
+  flex-direction: column;
+  gap: 6px;
+  margin-bottom: var(--sp-3);
+}
+
+.admin-token-row {
+  display: flex;
+  align-items: center;
+  gap: var(--sp-3);
+  font-size: 0.8rem;
+}
+
+.admin-token-scopes {
+  font-family: var(--mono);
+  color: var(--ds-text);
+}
+
+.admin-token-meta {
+  color: var(--ds-muted);
+  flex: 1;
+}
+
+.admin-token-revoke {
+  background: transparent;
+  border: none;
+  color: var(--ds-danger);
+  font-size: 0.76rem;
+  cursor: pointer;
+}
+
+.admin-issue-token {
+  display: flex;
+  align-items: center;
+  gap: var(--sp-3);
+  flex-wrap: wrap;
+}
+
+.admin-scope-checkbox {
+  display: flex;
+  align-items: center;
+  gap: 4px;
+  font-size: 0.78rem;
+  font-family: var(--mono);
+  color: var(--ds-muted);
+}
+
+.admin-new-token {
+  margin-top: var(--sp-3);
+  font-size: 0.8rem;
+  color: var(--ds-accent);
+}
+
+.admin-new-token code {
+  background: var(--ds-surface-2);
+  padding: 3px 8px;
+  border-radius: 6px;
+  word-break: break-all;
+}
+
+.admin-subheading {
+  font-size: 0.95rem;
+  margin: var(--sp-6) 0 var(--sp-3);
+}