feat(FN-3950): reuse keyboard-aware room thread container (+3 more)

Commits merged:
- fix(FN-3950): replace graph task rgba highlights with color tokens
- test(FN-3950): add room mobile keyboard anchoring regression coverage
- fix(FN-3950): enable mobile keyboard tracking for room threads
- feat(FN-3950): complete Step 1 — reuse keyboard-aware room thread container

Files changed:
docs/dashboard-guide.md                            |  1 +
 packages/dashboard/app/components/ChatView.tsx     | 11 ++-
 .../components/__tests__/ChatView.rooms.test.tsx   | 88 +++++++++++++++++++++-
 3 files changed, 93 insertions(+), 7 deletions(-)

Fusion-Task-Id: FN-3950

docs/dashboard-guide.md

@@ -112,6 +112,7 @@ Chat Rooms are project-scoped group conversations for multiple agents. They are
 - Selecting a room opens the room thread pane with loading and empty states, then renders room messages from `rooms.messages` as `ChatMessageInfo` entries in the same thread UI used for direct Chat.
 - Submitting the room composer calls `rooms.sendRoomMessage(...)`, which posts the user message to `POST /api/chat/rooms/:id/messages`.
 - After a successful room send, the room composer is cleared (matching direct-chat composer behavior) so stale text is not left in the input.
+- On mobile, room threads use the same keyboard-aware thread anchoring as direct chat, keeping the composer pinned above the soft keyboard while typing.
 - The dashboard backend now orchestrates room responders on that POST: mentioned members are routed as direct responders, additional ambient members may reply (up to the room ambient responder cap), and each assistant reply is persisted with `senderAgentId` via `chatStore.addRoomMessage(...)`.
 - The UI still avoids optimistic room echo; it renders both the persisted user message and persisted assistant room replies from `chat:room:message:*` SSE events, so room threads stay server-authoritative.
 - Relationship summary: direct Chat runs one target (agent or model) per session; rooms are shared threads with multiple agent members and now use the same message contract as direct Chat; Quick Chat stays a floating single-target panel and does not host rooms.