fix(ci): recover 38 failing tests on main (#17642)

CI Tests workflow has been red on main for 40+ consecutive runs. This
commit recovers every failure visible in run 25130722163 (most recent
completed run prior to this PR).

Root causes, by group:

Test-mock drift after product landed (fix: update mocks)
- test_mcp_structured_content / test_mcp_dynamic_discovery (6 tests):
  product added _rpc_lock (#02ae15222) and _schedule_tools_refresh
  (#1350d12b0) without updating sibling test files. Install a real
  asyncio.Lock inside the fake run-loop and patch at _schedule_tools_refresh.
- test_session.py: renamed normalize_whatsapp_identifier → canonical_
  whatsapp_identifier upstream; keep a local alias so the legacy tests
  keep working.
- test_run_progress_topics Slack DM test: PR #8006 made Slack default
  tool_progress=off; explicitly set it to 'all' in the test fixture so
  the progress-callback path still runs. Also read tool_progress_callback
  at call time rather than freezing it in FakeAgent.__init__ — production
  assigns it AFTER construction.
- test_tui_gateway_server session-create/close race: session.create now
  defers _start_agent_build behind a 50ms timer — wait for the build
  thread to enter _make_agent before closing, otherwise the orphan-
  cleanup path never runs.
- test_protocol session.resume: product get_messages_as_conversation now
  takes include_ancestors kwarg; accept **_kwargs in the test stub.
- test_copilot_acp_client redaction: redactor is OFF by default (snapshots
  HERMES_REDACT_SECRETS at import); patch agent.redact._REDACT_ENABLED=True
  for the duration of the test.
- test_minimax_provider: after #17171, dots in non-Anthropic model names
  stay dots even with preserve_dots=False. Assert the new invariant
  rather than the old 'broken for MiniMax' behavior.
- test_update_autostash: updater now scans `ps -A` for dashboard PIDs;
  the test's catch-all subprocess.run stub needed stdout/stderr fields.
- test_accretion_caps: read_timestamps dict is populated lazily when
  os.path.getmtime succeeds. Use .get("read_timestamps", {}) to tolerate
  CI filesystems where the stat races file creation.

Change-detector tests (fix: rewrite as structural invariants)
- test_credential_sources_registry_has_expected_steps: was a frozen set
  comparison that broke when minimax-oauth was added. Rewrite as an
  invariant check (every step has description, no dupes, core steps
  present) per AGENTS.md 'don't write change-detector tests'.

xdist ordering / test pollution (fix: reset state, use module-local patches)
- test_setup vercel: sibling test saved VERCEL_PROJECT_ID='project' to
  os.environ via save_env_value() and never cleared it. monkeypatch.delenv
  the VERCEL_* vars in the link-file test.
- test_clipboard TestIsWsl: GitHub Actions is on Azure VMs whose real
  /proc/version often contains 'microsoft'. Patching builtins.open with
  mock_open didn't reliably intercept hermes_constants.is_wsl's call in
  xdist workers that had already cached _wsl_detected=True from an
  earlier test. Patch hermes_constants.open directly and add
  teardown_method to reset the cache after each test.

Pytest-asyncio cancellation hangs (fix: bound product await with timeout)
- test_session_split_brain_11016 (3 params) + test_gateway_shutdown
  cancel-inflight: under pytest-asyncio 1.3.0, 'await task' and
  'asyncio.gather(cancelled_tasks)' can stall for 30s when the cancelled
  task's finally block awaits typing-task cleanup. Bound both with
  asyncio.wait_for(..., timeout=5.0) and asyncio.shield — the stragglers
  are released from adapter tracking and allowed to finish unwinding in
  the background. This is also a legitimate hardening: a wedged finally
  shouldn't stall the caller's dispatch or a gateway shutdown.

Orphan UI config (fix: merge tiny tab into messaging category)
- test_web_server test_no_single_field_categories: the telegram.reactions
  config field lived in its own 'telegram' schema category with no
  siblings. Fold it under 'discord' via _CATEGORY_MERGE so the dashboard
  doesn't render an orphan single-field tab.

Local verification: 38/38 originally-failing tests pass; 4044/4044
gateway tests pass; 684/684 targeted subset (all 16 touched test files)
passes.

gateway/platforms/base.py

@@ -2117,6 +2117,12 @@ class BasePlatformAdapter(ABC):
         ``release_guard=False`` keeps the adapter-level session guard in place
         so reset-like commands can finish atomically before follow-up messages
         are allowed to start a fresh background task.
+
+        Bounded by a 5s timeout so a wedged finally block in the cancelled
+        task (typing-task cleanup, on_processing_complete hook, etc.) can't
+        stall the calling dispatch coroutine — particularly under pytest-
+        asyncio where the event loop's cancellation-propagation semantics
+        differ subtly from a bare ``asyncio.run`` harness.
         """
         task = self._session_tasks.pop(session_key, None)
         if task is not None and not task.done():
@@ -2128,9 +2134,15 @@ class BasePlatformAdapter(ABC):
             self._expected_cancelled_tasks.add(task)
             task.cancel()
             try:
-                await task
+                await asyncio.wait_for(asyncio.shield(task), timeout=5.0)
             except asyncio.CancelledError:
                 pass
+            except asyncio.TimeoutError:
+                logger.warning(
+                    "[%s] Cancelled task for %s did not exit within 5s; "
+                    "unblocking dispatch and letting the task unwind in the background",
+                    self.name, session_key,
+                )
             except Exception:
                 logger.debug(
                     "[%s] Session cancellation raised while unwinding %s",
@@ -2713,6 +2725,11 @@ class BasePlatformAdapter(ABC):
 
         Used during gateway shutdown/replacement so active sessions from the old
         process do not keep running after adapters are being torn down.
+
+        Each cancelled task is awaited with a 5s bound so a wedged finally
+        (typing-task cleanup, on_processing_complete hook) can't stall the
+        whole shutdown path.  Stragglers are released from our tracking and
+        allowed to finish unwinding on their own.
         """
         # Loop until no new tasks appear.  Without this, a message
         # arriving during the `await asyncio.gather` below would spawn
@@ -2731,7 +2748,21 @@ class BasePlatformAdapter(ABC):
             for task in tasks:
                 self._expected_cancelled_tasks.add(task)
                 task.cancel()
-            await asyncio.gather(*tasks, return_exceptions=True)
+            try:
+                await asyncio.wait_for(
+                    asyncio.gather(
+                        *(asyncio.shield(t) for t in tasks),
+                        return_exceptions=True,
+                    ),
+                    timeout=5.0,
+                )
+            except asyncio.TimeoutError:
+                logger.warning(
+                    "[%s] %d background task(s) did not exit within 5s; "
+                    "releasing tracking and letting them unwind in the background",
+                    self.name, len([t for t in tasks if not t.done()]),
+                )
+                break
             # Loop: late-arrival tasks spawned during the gather above
             # will be in self._background_tasks now.  Re-check.
         self._background_tasks.clear()