Record why a subscription reading was refused, and read the outcome from the last word

[drevendev]

Closes #168

Achieved outcome

A refused subscription reading now records the API's own error type in its reason (HTTP 403 permission_error) and keeps the error message in the reading, which reaches the private ledger only; the public warning prints the reason alone, and the token appears in neither. The outcome of a run is classified from its final message, and a handoff or a verdict marker there means completed whatever else the message mentions; blocker markers are consulted only after that.

Tested revision

d8a41a5

Changed artifacts

• scripts/subscription_usage.py — error_detail() reads at most 64 KB of a refusal body and returns error.type and a 200-character error.message; unavailable() and the success reading carry an error_message field; the HTTP branch of read() uses both.
• scripts/record_usage.py — COMPLETED markers (handoff, verdict, a named pull request); final_text() returns the result text or the last assistant text; classify_outcome() checks COMPLETED before BLOCKED; main() classifies from final_text() while mentions and rework still read the whole transcript.
• scripts/tests/test_subscription_usage.py — refusal with a JSON body, without a JSON body, with no body, and with an overlong message; the token never appears in a reading.
• scripts/tests/test_record_usage.py — the Implement buildInitialWorld() 17-step initialization (REQ-CONFIG-003) #163 case (handoff plus a blocked mention is completed), acceptor verdicts, a blocker heading without a handoff, and final_text() in three shapes.

Acceptance criteria

• A 403 whose body names permission_error is recorded with reason HTTP 403 permission_error and the message in the reading; a body that is not JSON leaves reason HTTP 403 and no message; the token appears nowhere in either — test_a_refusal_records_the_status_and_the_error_type_and_keeps_the_message, test_a_refusal_without_a_json_body_records_the_status_code_only, test_a_refusal_with_no_body_at_all_is_still_recorded.
• A final message carrying ## AUTHOR handoff and a pull request number classifies as completed even if it also says something is blocked; a final message carrying ## AUTHOR blocker classifies as blocked — test_a_handoff_is_completed_whatever_else_it_mentions, test_a_blocker_heading_without_a_handoff_is_still_blocked.
• python -m unittest discover -s scripts/tests passes — 275 tests at d8a41a5.

Checks

Check	Outcome	Evidence
python -m unittest discover -s scripts/tests	passed	275 tests, OK, at d8a41a5
python scripts/policy_guard.py --base origin/master	passed	policy paths only, no violation
dotnet build --configuration Release / dotnet test	not_run	no product code changed; the required check runs it on this pull request. Risk left open: none for this diff
npm run typecheck && npm test && npm run build	not_run	same

Not checked

The live 403 body. The first run after merge records it; the reason then names the error type and the ledger holds the message, which is what decides the next step on the subscription figure.

Assumptions and unknowns

• Anthropic error bodies are JSON of the shape {"type": "error", "error": {"type": ..., "message": ...}}. Any other shape degrades to the status code alone.
• The error message never contains the token. It is capped at 200 characters and stored in the private ledger only, so even a surprising message stays off the public log.
• COMPLETED is a heuristic like the rest of the classifier and is marked heuristic in the record. A run that opens a pull request and then reports a blocker in the same final message is recorded as completed; that is the intended reading — a pull request exists.

Highest-risk area for review

COMPLETED in record_usage.py: too broad a pattern would hide genuinely blocked runs behind any mention of a pull request. It is anchored to headings for the role markers and requires a number for the pull request forms; OutcomeTests carries the negative controls.

Remaining gate

None mandatory. Narrowing in substance: nothing new is printed except an error type, and no credential enters any workflow.