[R115] originate ci_watch/dep_update fix tasks as PLANNING coordination roots

The Main-PM-code-impossibility guard (commit e202ce39, Thread 4 of this
audit) made team=MAIN_PM + task_type=CODE impossible — a Main PM coordinates,
it does not write code. But the ci_watch and dep_update engines still
originated their fix tasks as task_type=TaskType.CODE assigned to main-pm,
so task_svc.create raised MAIN_PM_NO_CODE and NO fix task was ever opened
— a regression introduced by the earlier audit fix (confirmed: the engine
tests pass at e202ce39~1 and fail at HEAD).

Mirror the hardened self_heal_engine precedent (self_heal_engine.py:197)
which already uses task_type=TaskType.PLANNING for its Main-PM coordination
root with an explicit 'decompose the fix and delegate the code work to a
cell dev — the Main PM does not write the fix itself' description. Both
engines now originate PLANNING coordination roots with matching delegation
guidance in the description + acceptance criteria. confirmed_by_human
stays True for both (they ride the normal delivery flow without the CEO
gate, unlike self-heal — intentional per the architecture).

The dedupe/open-cap queries (list_open_ci_watch_tasks /
list_open_dep_update_tasks) key on source + non-terminal status + git_url,
NOT task_type, so the type change does not break dedup (still one open fix
task per repo).

The two source-test fixtures (test_ci_watch_source / test_dep_update_source)
created CODE+MAIN_PM tasks directly to exercise the listing queries — same
guard violation; switched to PLANNING (the queries assert on source/status,
not task_type, so the fixture type matches the engines' corrected type).

tests/integration/services/test_ci_watch_source.py

@@ -86,7 +86,7 @@ async def _make_ci_watch_task(
             team=Team.MAIN_PM,
             assigned_to=MAIN_PM_UUID,
             created_by=SYSTEM_UUID,
-            task_type=TaskType.CODE,
+            task_type=TaskType.PLANNING,
             nature=TaskNature.TECHNICAL,
             estimated_complexity=Complexity.MEDIUM,
             project_id=cast("UUID", project.id),

tests/integration/services/test_dep_update_source.py

@@ -84,7 +84,7 @@ async def _make_task(
             team=Team.MAIN_PM,
             assigned_to=MAIN_PM_UUID,
             created_by=SYSTEM_UUID,
-            task_type=TaskType.CODE,
+            task_type=TaskType.PLANNING,
             nature=TaskNature.TECHNICAL,
             estimated_complexity=Complexity.MEDIUM,
             project_id=cast("UUID", project.id),