feat(tasks): task-content guardrails — structured plans + constraints split (#328)

* feat(tasks): task-content guardrails — structured plans + constraints split

Bound task PLANNING content the way journals/notes already are, fixing the
poor task quality flagged 2026-07-07 (degenerate roots, over-decomposed
leaves, descriptions bloated by an auto-attached conventions dump).

Phase A — plan/AC guardrails (no migration):
- _pm_sub_tasks_gate: cap sub_tasks at 7; per-subtask ceilings (title <=200,
  description <=600) enforced at both the Pydantic boundary and the gate.
  Dropped the min-2-roots and no-subtasks-on-code rules: both contradict the
  2026-05-08 rule (test_cell_pm_can_plan_code_typed_parent_via_i_will_plan)
  and break legitimate single-cell roots. Long comment in the gate explains.
- IWillPlanRequest: plan <=2000, approach <=800 (floor 150 kept), typed
  SubTaskCreate/RiskCreate/OpenQuestionCreate replacing loose list[dict].
- DelegateRequest + task_completeness: acceptance_criteria capped at 7 items,
  each <=200 chars. New FieldRule.MAX_LENGTH_LIST + _post_rule_reject helper
  (extracted to keep the gate under xenon B).
- Routes dump typed models to dicts for the existing rich_plan shaper.

Phase B — conventions split (migration 068):
- New nullable tasks.constraints Text column; _attach_baseline_constraints
  now writes the ## Constraints block there instead of appending to
  description, so description is the human-authored instruction only. The
  conventions still reach the agent independently at spawn via the ambient
  block, so agent correctness is unaffected.
- TaskResponse / Task model / panel Task type carry constraints; panel shows
  a read-only Constraints card. Field is optional on the TS type (backend
  returns null for flag-off / pre-migration rows).

Tests: 5 new gate unit tests, 7 schema tests, 3 AC policy tests, 3 e2e smoke
scenarios; 4 baseline-constraints integration tests updated. ruff/mypy/xenon
clean; 10026 unit+foundation+e2e green; panel typecheck clean.

Refs: plan breezy-imagining-kahn

* test(tasks): use typed SubTaskCreate instead of dict literals in plan tests

make quality runs mypy over tests/ (1079 files), not just roboco/ — the
four sites passing dict literals to the now-typed sub_tasks: list[SubTaskCreate]
field failed mypy. Construct SubTaskCreate directly; the typed model raising
ValidationError IS the boundary the rejection tests assert.

* fix(deps): drop unused python-jose — clears PYSEC-2026-1325 (ecdsa, no fix)

CI's pip-audit went red on a freshly-published advisory PYSEC-2026-1325
against ecdsa 0.19.2 (no fix published — 0.19.2 is the latest). ecdsa is a
transitive dep of python-jose, which is a DIRECT dep of roboco but is NOT
imported anywhere in roboco/ or tests/ (grep-verified). The actual JWT path
uses PyJWT (import jwt) + fastapi_users.jwt, not python-jose.

So python-jose is a dead dependency. Removing it (deletion over an
--ignore-vuln waiver) drops ecdsa + rsa + pyasn1 + their type stubs from the
lockfile, eliminating the CVE at the source. deptry roboco/ stays clean
(no missing-dep), mypy clean, auth + schema tests pass.

Master CI was green 9h before this PR's run, so the advisory published in
that window would red any run including master — this fix unblocks both.

* chore(prompts): regenerate verb tables for typed plan sub_tasks

Phase A's IWillPlanRequest schema change (sub_tasks/risks/open_questions from
loose list[dict] to typed SubTaskCreate/RiskCreate/OpenQuestionCreate) made
the auto-generated verb tables stale. Regenerated via
scripts/regenerate_verb_tables.py — the diff is purely the signature
reflection (list[str|str] -> list[SubTaskCreate], etc.). Required by the
foundation-check gate (Makefile:559).

---------

Co-authored-by: Renn F <rennf93@users.noreply.github.com>

tests/integration/test_task_baseline_constraints.py

@@ -68,9 +68,12 @@ async def test_baseline_attached_when_flag_on(
     monkeypatch.setattr(settings, "conventions_enabled", True)
     agent, project = await _seed(db_session)
     task = await TaskService(db_session).create(_req(agent, project, "Do the work"))
-    assert task.description is not None
-    assert "## Constraints" in task.description
-    assert "no lint suppressions" in task.description
+    # The conventions block lives in `constraints`, not `description` (the
+    # 2026-07-07 fix: description is the human-authored instruction only).
+    assert task.description == "Do the work"
+    assert task.constraints is not None
+    assert "## Constraints" in task.constraints
+    assert "no lint suppressions" in task.constraints
 
 
 async def test_flag_off_attaches_nothing(
@@ -80,20 +83,24 @@ async def test_flag_off_attaches_nothing(
     agent, project = await _seed(db_session)
     task = await TaskService(db_session).create(_req(agent, project, "Do the work"))
     assert task.description == "Do the work"
+    assert task.constraints is None
 
 
 async def test_baseline_not_suppressed_by_agent_constraints_section(
     db_session: AsyncSession, monkeypatch: pytest.MonkeyPatch
 ) -> None:
-    # An agent-authored ## Constraints section must NOT suppress the mandatory
-    # server baseline — both are present.
+    # An agent-authored ## Constraints section in the description must NOT
+    # suppress the mandatory server baseline — the description keeps the
+    # agent's block and `constraints` carries the server baseline (separate
+    # field, so neither suppresses the other).
     monkeypatch.setattr(settings, "conventions_enabled", True)
     agent, project = await _seed(db_session)
     seeded = "Do the work\n\n## Constraints\n- a task-specific note"
     task = await TaskService(db_session).create(_req(agent, project, seeded))
     assert task.description is not None
     assert "a task-specific note" in task.description
-    assert "no lint suppressions" in task.description
+    assert task.constraints is not None
+    assert "no lint suppressions" in task.constraints
 
 
 async def test_baseline_attach_is_idempotent(
@@ -103,8 +110,8 @@ async def test_baseline_attach_is_idempotent(
     agent, project = await _seed(db_session)
     svc = TaskService(db_session)
     task = await svc.create(_req(agent, project, "Do the work"))
-    before = task.description
+    before = task.constraints
     await svc._attach_baseline_constraints(task)
-    assert task.description == before
-    assert task.description is not None
-    assert task.description.count("no lint suppressions") == 1
+    assert task.constraints == before
+    assert task.constraints is not None
+    assert task.constraints.count("no lint suppressions") == 1