Step 2 of removing Zed's hosted collab feature from PaddleBoard.

The file finder used to surface "Channel Notes" entries inline with
file matches, dispatching workspace::OpenChannelNotesById on confirm.
Without the channel/collab_ui crates there's no channel store to
read from, so drop the entire Match::Channel variant and every
match arm that handled it.

- Remove Match::Channel from the Match enum and every place it's
  matched (relative_path, abs_path, panel_match, match_score,
  labels_for_match, confirm, render_match, and the test helpers).
- Remove the channel-matching block (~60 lines) that read channels
  from ChannelStore and scored them by name.
- Drop the channel_store field from FileFinderDelegate.
- Drop channel, client, and fuzzy from file_finder/Cargo.toml.
  `fuzzy::StringMatch{,Candidate}` were only used by the channel
  path; `client::ChannelId` likewise.

cargo check -p file_finder --tests is clean. The include_channels
setting in FileFinderSettings stays (settings_content/open_path_prompt
crates untouched); it just no longer has anything to gate.

Release Notes:

- Removed the file finder's "Channel Notes" inline matches (Zed Cloud collab feature, never functional in PaddleBoard).

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

Step 3 of removing Zed's hosted collab feature from PaddleBoard.

NotificationStore handled the rpc::Notification stream from the
Zed Cloud collab server: contact requests, channel invitations,
channel-message mentions. Without the channel/collab_ui crates
there's nothing left to surface from it. Only collab_ui (going
away) and collab integration tests (going away) used it.

The local StatusToast UI is a separate surface in this same crate
and stays — agent_ui, keymap_editor, etc. all use it.

- Delete crates/notifications/src/notification_store.rs (428 LOC).
- Reduce notifications.rs to just `pub mod status_toast;`.
- Strip channel, client, rpc, sum_tree, time, anyhow, futures-lite,
  util from Cargo.toml — all were only used by NotificationStore.

cargo check -p notifications is clean. paddleboard still calls
notifications::init() (in main.rs and zed.rs) which no longer
exists; those call sites are removed in a later commit on this
branch as part of stripping paddleboard's collab_ui wiring.

Release Notes:

- N/A

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

Step 4 of removing Zed's hosted collab feature from PaddleBoard.

When committing inside a Zed Cloud collab room, the git panel
suggested everyone in the room as a "Co-authored-by:" line on
the commit message. Without the call/channel crates there is no
room to read from, so collapse the entire feature.

- potential_co_authors becomes a no-op returning Vec::default().
- Delete local_committer(&self, room: &call::Room, ...) which read
  the local participant from the room.
- Delete pub fn load_local_committer and its commit_modal caller;
  it cached the local git committer for the room-suggestion path,
  which no longer exists.
- Remove the local_committer and local_committer_task fields and
  their constructor inits.
- In Render::render, drop the `let room = ...` binding and replace
  has_co_authors with `false`. The ToggleFillCoAuthors action is
  still defined but the action handler is gated on
  has_write_access && has_co_authors so it stays disabled.
- Drop GitCommitter / get_git_committer imports (only used by the
  removed code path) and call from git_ui/Cargo.toml.

cargo check -p git_ui is clean. The add_coauthors field,
toggle_fill_co_authors action handler, render_co_authors helper,
and fill_co_authors method are intentionally preserved: they're
gated on potential_co_authors being non-empty, so they short-
circuit safely. Keeping them minimizes the upstream-file diff.

Release Notes:

- Removed the git panel's "suggest co-authors from collab room" feature (Zed Cloud collab feature, never functional in PaddleBoard).

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

Drops the collab_ui crate as a paddleboard dependency and removes every
call site that pulled CollabPanel / ChannelView / collab_ui::init into
the running app: main.rs init block + zed-link URL handling + zed.rs
panel registration and ToggleFocus action + View > Collab Panel menu
item + the test bootstrap. Also drops two notifications::init(...)
calls that were left behind when the Zed Cloud NotificationStore was
deleted.

The collab_ui crate stays in the workspace tree (still has compile
errors from prior surface rips); it just is not compiled into the
paddleboard binary anymore. This makes the workspace.rs AutoWatch /
screen-share / leader-routing surface truly dead, which a follow-up
commit can then strip without the collab_ui consumer ghost-pinning it.

Also drops a stale call::RemoteParticipant doc comment from the
workspace shim that it abstracts away.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>