Fix send_message compose chain against the real Kaiser contract

[hugooc]

send_message had never succeeded once. The commit path failed at the first call with GetComposeId response missing composeId (response keys: str), and ~/.openkp/audit.log had no phase="result" line anywhere in its history.

Why the tests didn't catch it

The send chain's response shapes were inferred from HAR content.size values, never captured. Chrome DevTools' HAR exporter has a small circular buffer and the 690 KB GetConversationList response evicted every body in the compose flow — messages.md documented this gap honestly. The tests then mocked those inferred shapes, so a fully green suite certified a guess.

Three divergences, all verified live 2026-07-29

1. GetComposeId returns a bare JSON string. The whole 130-byte body is "WP-<128 chars>", so response.json() yields a str. The parser looked for a composeId key on a dict that never existed. Not double-encoded either — a second json.loads raises JSONDecodeError. The HAR sizes (130, 130, 126 across three captures) were consistent with a bare token all along.

2. GetViewers was never called. VIEWERS_PATH was defined and unused, so viewers[0].wprId went out empty. The captures show it populated with an 84-char token. Kaiser rejects the draft with {"error": 2}.

3. The recipient object carried 12 keys. All three captures show the browser trimming to exactly five: displayName, userId, poolId, providerId, departmentId. poolId and departmentId are empty in the browser too, so empty there is correct and not a failed lookup.

Changes

• _extract_token accepts bare-string or wrapped token responses, so neither form can break the chain again
• _describe_payload reports type: str instead of keys: str — the old wording read as a key list containing "str" and sent debugging after a missing field on a non-existent object
• _post_get_viewers calls GetViewers and picks the isSelf entry. Never raises; a failure degrades to the previous fallback rather than blocking a send
• _RECIPIENT_KEYS pins the recipient payload to the browser's five

Note on error codes

Kaiser returns application errors as HTTP 200 with {"error": N}, so raise_for_status() does not catch them. SaveDraft returns error: 0 on success alongside conversationId. Documented but deliberately not enforced — we still key off a missing conversationId rather than error != 0. Worth a follow-up.

Since both divergences were fixed at once, which one {"error": 2} was complaining about is not established. Recorded as observational.

Verified

596 tests pass. Message sent live 2026-07-29 15:10:05 UTC — the first successful phase="result" in the audit log.

messages.md now marks GetComposeId, GetViewers, SaveDraft, and the recipient key set as verified live, with the byte arithmetic behind each.

🤖 Generated with Claude Code