CB-622: rename bridge_* tool names to fleet_* in Markdown docs

Rename the eleven MCP tool names (bridge_ack/ask/list/poll/profiles/reply/
send/spawn/status/stop/whoami) to their fleet_* names across the Markdown
documentation. fleet_* is written as the normal name; one deprecation note
in README.md says bridge_* still works for one release.

docs/MCP-Contract.md is renamed only inside section 6 (lines 210-293):
sections 1-5 and 7-11 are stale pre-build design text (CB-609) and are
deliberately left with old names so dead text does not look maintained.

Also renames e2e/bridge_ask_transcript.md to e2e/fleet_ask_transcript.md
to match its content. CLAUDE.md, wiki/, plugin/skills/setup/SKILL.md and
.claude/skills/port-to-opencode/SKILL.md are owned by other units and are
untouched.

docs/Worker-Git-Workflow.md

@@ -20,7 +20,7 @@ requirement, not a nice-to-have.**
 - **Worktree provisioned by the daemon** — `SessionManager` creates a dedicated git worktree +
   branch per session, **hydrates it to full config parity** (below), and tears it down on release.
 - **Worker opens its own PR** — the worker commits, pushes its branch, and opens the PR/MR itself,
-  returning the PR URL in its `bridge_reply`.
+  returning the PR URL in its `fleet_reply`.
 
 ## Why worktrees (the hazard being fixed)
 
@@ -103,7 +103,7 @@ sequenceDiagram
     Note over W: implement in the isolated worktree
     W->>G: git commit + git push (SSH, same user)
     W->>G: open PR (branch to main)
-    W-->>P: bridge_reply (prUrl, branch, summary, tests)
+    W-->>P: fleet_reply (prUrl, branch, summary, tests)
     P->>SM: release(paneId)
     SM->>G: git worktree remove wt
     Note over G: branch + PR persist for review/merge
@@ -170,7 +170,7 @@ A worker-facing playbook (sibling to the existing `reviewer` skill):
 3. **Push** your branch (`git push -u origin HEAD`).
 4. **Open a PR** to `main` (option A `curl`, or the decided mechanism) with a title/body describing
    the change and referencing the ticket.
-5. **Reply** via `bridge_reply` with the **PR URL**, branch name, files changed, and test names —
+5. **Reply** via `fleet_reply` with the **PR URL**, branch name, files changed, and test names —
    that reply is the whole handoff.
 6. Do **not** merge; do **not** touch `.mcp.json` or `wiki/`.