Board Program LEARN context, ruff 0.16, and verb-rejection observability (#700)

* fix(board): LEARN decisions name the item, not its per-cycle index

A cycle's reject reasons are rendered into the NEXT cycle's exploration
prompt, but the ref recorded alongside each reason was the item's stored
id (item-0/item-1) — a per-cycle index that means something different
every cycle and appears nowhere the explorer can resolve. The reason
survived the loop; what it was about did not.

Record the item's title instead, via a shared learn_ref() helper (falls
back to the id when title-less, and reads target_task_title for Scales,
whose items name the live task they mutate).

* chore(lint): satisfy ruff 0.16 — keyword-only signatures and markdown formatting

The dev toolchain resolved ruff 0.16.0, which stabilises PLR0917 (too many
positional arguments) and formats python code blocks inside markdown. Both
fired repo-wide and neither had anything to do with the code they flagged.

- 36 signatures gain a `*` so their tail arguments are keyword-only, and
  the 104 call sites that passed them positionally are converted. mypy was
  the safety net for the static ones; the full suite caught nine more that
  only bind at runtime (the MCP tool functions, whose real callers already
  pass named JSON arguments).
- 28 markdown files reformatted by 0.16's code-block formatter.
- One RUF036 (`None` mid-union) autofixed in the GitLab provider.

* fix(gateway): log the reason when a verb rejects

A rejected envelope rides an HTTP 200, its body is never logged, and there
is no trace table — so in the access log a verb an agent could not satisfy
looks identical to one that worked. On 2026-07-25 four Board Programs
(Periscope, Sentinel, Scales, Barfly) each POSTed their propose verb three
or four times, persisted nothing, and left their exploration tasks PENDING;
the reason was unrecoverable afterwards, from the logs or from the agents'
own transcripts.

Log error/message/remediate/missing plus the calling agent at
envelope_to_response — the one chokepoint every v1 flow and do route
returns through. Success envelopes stay silent.

---------

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

tests/integration/test_full_lifecycle_real_db.py

@@ -352,8 +352,8 @@ async def test_dev_can_claim_pending_task_via_gateway(
     c = Choreographer(deps)
 
     env = await c.i_will_work_on(
-        dev_agent.id,
-        task.id,
+        agent_id=dev_agent.id,
+        task_id=task.id,
         plan=_GOOD_PLAN,
         steps=_STEPS,
         technical_considerations=_GOOD_TC,
@@ -401,8 +401,8 @@ async def test_dev_full_chain_through_awaiting_qa(
 
     # 1. Claim
     env = await c.i_will_work_on(
-        dev_agent.id,
-        task.id,
+        agent_id=dev_agent.id,
+        task_id=task.id,
         plan=_GOOD_PLAN,
         steps=_STEPS,
         technical_considerations=_GOOD_TC,
@@ -480,8 +480,8 @@ async def test_full_chain_through_doc_handoff(
 
     # Drive the dev side first (same as test_dev_full_chain_through_awaiting_qa).
     await c.i_will_work_on(
-        dev_agent.id,
-        task.id,
+        agent_id=dev_agent.id,
+        task_id=task.id,
         plan=_GOOD_PLAN,
         steps=_STEPS,
         technical_considerations=_GOOD_TC,

tests/integration/test_lifecycle_real_db.py

@@ -420,8 +420,8 @@ async def test_dev_full_chain_through_awaiting_qa(
     c = Choreographer(deps)
 
     env = await c.i_will_work_on(
-        dev_agent.id,
-        task.id,
+        agent_id=dev_agent.id,
+        task_id=task.id,
         plan=_GOOD_PLAN,
         steps=_STEPS,
         technical_considerations=_GOOD_TC,
@@ -906,8 +906,8 @@ async def test_block_then_unblock_restore(
 
     # Drive into in_progress via the real claim+start sequence.
     env = await c.i_will_work_on(
-        dev_agent.id,
-        task.id,
+        agent_id=dev_agent.id,
+        task_id=task.id,
         plan=_GOOD_PLAN,
         steps=_STEPS,
         technical_considerations=_GOOD_TC,
@@ -969,8 +969,8 @@ async def test_pause_then_resume(
     c = _build_choreographer(db_session, task, task_service)
 
     env = await c.i_will_work_on(
-        dev_agent.id,
-        task.id,
+        agent_id=dev_agent.id,
+        task_id=task.id,
         plan=_GOOD_PLAN,
         steps=_STEPS,
         technical_considerations=_GOOD_TC,

tests/integration/test_revision_findings_real_db.py

@@ -723,8 +723,8 @@ async def test_i_am_done_full_chain_blocks_then_resolves(
 
     # --- Round 1: no findings exist yet — i_am_done must pass untouched. ---
     env = await c.i_will_work_on(
-        dev_agent.id,
-        task.id,
+        agent_id=dev_agent.id,
+        task_id=task.id,
         plan=_GOOD_PLAN,
         steps=_STEPS,
         technical_considerations=_GOOD_TC,
@@ -784,8 +784,8 @@ async def test_i_am_done_full_chain_blocks_then_resolves(
     # re-enforces the rich-plan gate for a developer — so the full plan is
     # supplied again here, same as the very first claim. ---
     env = await c.i_will_work_on(
-        dev_agent.id,
-        task.id,
+        agent_id=dev_agent.id,
+        task_id=task.id,
         plan=_GOOD_PLAN,
         steps=_STEPS,
         technical_considerations=_GOOD_TC,

tests/integration/v1/test_full_pending_to_completed.py

@@ -57,13 +57,7 @@ class _MockChoreographer:
             next="claim it",
         )
 
-    async def i_will_work_on(
-        self,
-        _agent_id: object,
-        _task_id: object,
-        _plan: object = None,
-        **_kwargs: object,
-    ) -> Envelope:
+    async def i_will_work_on(self, **_kwargs: object) -> Envelope:
         self._state["task_status"] = "in_progress"
         return Envelope.ok(
             status="in_progress",