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/python-security.md

@@ -12,6 +12,7 @@ DATABASE_URL = "postgresql://user:password@host/db"
 # Good - environment variables
 from pydantic_settings import BaseSettings
 
+
 class Settings(BaseSettings):
     api_key: str
     database_url: str
@@ -27,9 +28,7 @@ NEVER use string concatenation for SQL:
 query = f"SELECT * FROM users WHERE id = '{user_id}'"
 
 # Good - parameterized query
-result = await session.execute(
-    select(User).where(User.id == user_id)
-)
+result = await session.execute(select(User).where(User.id == user_id))
 ```
 
 ## Command Injection Prevention
@@ -39,10 +38,12 @@ NEVER pass user input directly to shell:
 ```python
 # Bad - command injection
 import os
+
 os.system(f"process_file {filename}")
 
 # Good - use subprocess with list
 import subprocess
+
 subprocess.run(["process_file", filename], check=True)
 ```
 
@@ -56,6 +57,7 @@ result = eval(user_input)
 
 # Good - safe parsing
 import ast
+
 result = ast.literal_eval(user_input)  # Only literals
 ```
 
@@ -68,7 +70,7 @@ import hashlib
 
 content_hash = hashlib.md5(
     content.encode(),
-    usedforsecurity=False  # Required flag
+    usedforsecurity=False,  # Required flag
 ).hexdigest()[:12]
 ```