Closes the seven outstanding items from the @claude review on PR #741:
1. Add empty `tests/client/talk/__init__.py` for pytest discovery parity
with `tests/client/{collectives,news}/`.
2. Standardise boolean query params to integers — `includeStatus` was the
string `"true"` in `list_conversations`/`list_participants` while every
other flag (`noStatusUpdate`, `lookIntoFuture`, `setReadMarker`,
`includeLastKnown`) used `1`/`0`.
3. Replace the `app:install || app:enable` chain in the spreed install hook
with `app:install --keep-disabled --force || true; app:enable spreed`,
so unrelated install failures surface as a clear "app not found" from
`app:enable` rather than being silently masked.
4. Add `_validate_token()` (alphanumeric whitelist) and call it from all
six TalkClient methods that interpolate the token into a URL path —
defence-in-depth against pathological tokens reaching httpx.
5. Rename `TalkConversation.type` to `room_type` with `Field(alias="type")`
and `populate_by_name=True`, so the field no longer shadows Python's
builtin while preserving spreed's wire format on input. MCP responses
now serialize `room_type` (field name) instead of `type`.
6. `mark_as_read` now passes `json=body or None` so the bodyless
"mark everything as read" call doesn't send a spurious `{}` body and
`Content-Type: application/json` header.
7. `_validate_message_text` rejects whitespace-only messages, not just
empty strings.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>