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>

docs/rag/standards/testing.md

@@ -16,6 +16,7 @@ Use pytest-asyncio:
 ```python
 import pytest
 
+
 @pytest.mark.asyncio
 async def test_fetch_user() -> None:
     user = await fetch_user("test-123")
@@ -48,11 +49,12 @@ Use factory-boy for test data:
 ```python
 from factory import Factory, Faker, LazyAttribute
 
+
 class TaskFactory(Factory):
     class Meta:
         model = Task
 
-    title = Faker('sentence')
+    title = Faker("sentence")
     status = TaskStatus.PENDING
     created_at = LazyAttribute(lambda _: datetime.now(UTC))
 ```
@@ -84,7 +86,7 @@ When you assign `None` to an attribute inside a test function, mypy narrows that
 def test_example() -> None:
     t = _Task()
     t.notes = None  # mypy narrows type to None
-    process(t)      # Even though process may write to t.notes
+    process(t)  # Even though process may write to t.notes
     assert t.notes is not None  # [unreachable] — mypy sees this as always False
 ```
 
@@ -94,11 +96,12 @@ def test_example() -> None:
 # ✅ GOOD: Annotation-typed class preserves union type
 class _TaskWithNoNotes:
     """Variant where notes starts as None (no prior state)."""
-    
+
     def __init__(self) -> None:
         self.id = uuid4()
         self.notes: dict[str, Any] | None = None  # Declared as union, not narrowed
-        
+
+
 def test_example() -> None:
     t = _TaskWithNoNotes()  # Use the helper instead
     process(t)