FN-7364: hide task chats from common feed by default

Hide task-detail planner chats from the common Chat feed unless a project opts in.

- Add a project setting and Settings UI toggle for showing populated task chats in the common feed.
- Filter task-planner sessions on chat list routes and avoid stale cached/SSE planner rows in the Chat hook.
- Cover default-hidden and opt-in behavior with route, hook, settings, and parity tests.
- Document the Chat feed behavior and include a patch changeset.

Files changed:
 .changeset/fn-7364-task-chat-feed-setting.md       |  7 ++
 docs/dashboard-guide.md                            |  2 +
 .../core/src/__tests__/settings-parity.test.ts     |  8 +++
 packages/core/src/settings-schema.ts               |  5 ++
 packages/core/src/types.ts                         |  5 ++
 .../__tests__/SettingsModal.general.test.tsx       | 18 +++++
 .../settings/sections/GeneralSection.tsx           |  9 +++
 .../dashboard/app/hooks/__tests__/useChat.test.ts  | 65 +++++++++++++++++
 packages/dashboard/app/hooks/useChat.ts            | 22 ++++--
 .../dashboard/src/__tests__/chat-routes.test.ts    | 82 +++++++++++++++++++++-
 .../dashboard/src/routes/register-chat-routes.ts   | 13 +++-
 11 files changed, 227 insertions(+), 9 deletions(-)

Fusion-Task-Id: FN-7364
Fusion-Task-Lineage: 79a0706c-ba7f-4417-b88b-c5282ae7877c
Co-authored-by: Fusion (runfusion.ai) <noreply@runfusion.ai>

docs/dashboard-guide.md

@@ -403,6 +403,8 @@ Chat view provides project-scoped conversations with agents.
 - On mobile direct-chat threads, entering a thread and restoring Chat after tab/page visibility returns re-anchors to the newest message (`scrollTop = scrollHeight`) so the view always opens at the live tail.
 - On mobile direct-chat threads, tapping the active title/identity in the thread header opens a lightweight conversation dropdown so you can switch to another direct session or start a New Chat without backing out to the sidebar list first; long conversation titles now stay readable in the dropdown via wrapped option text and taller touch-friendly rows.
 - Direct chat sessions can be renamed from the desktop conversation context menu and from the mobile session switcher; blank rename submissions clear the custom title so the default session label is shown again.
+<!-- FNXC:ChatViewDocs 2026-07-01-00:00: Task-detail planner chats are intentionally hidden from the common Direct feed by default after issue #1850; Settings keeps an opt-in for operators who want populated task-planner sessions restored without adding a mandatory Tasks tab. -->
+- Task-detail planner Chat conversations stay available from each task's **Chat** tab. They are hidden from the common Direct/common Chat feed by default; enable **Settings → Project General → Show task chats in common Chat feed** to include populated task chats again. Empty task chat sessions stay hidden either way.
 <!-- FNXC:ChatContextWindow 2026-06-27-00:00: Direct-chat docs must describe the desktop/tablet-only estimated token budget indicator and its intentional absence from mobile, narrow floating chat, and room headers. -->
 - On desktop/tablet Direct chat, the thread header shows an estimated token count against the active model's known context window (for example `~12.3k / 200k`). It is hidden on mobile, narrow floating chat, rooms, and unknown-context-window models.
 <!-- FNXC:ChatViewDocs 2026-06-28-14:52: Chat responsive docs must reflect that narrow chat hosts now key bubble width off the ChatView container, not just viewport media, so Quick Chat popups and the right dock on desktop viewports get the same full-width bubbles as phone Chat. -->