v4.4.2 — transport dispatch parity, worker contracts, token extraction robustness

Fixed

• HTTP transport dispatches all 21 advertised tools — slack_workflow_save, slack_workflows, and the three hosted upgrade stubs previously returned unknown_tool over HTTP. Both transports now route through a shared handler map, with a schema test guarding against future drift between tools/list and the dispatch surface.
• Worker tool contracts — slack_users_search paginates users.list (explicit scan cap + truncated flag) and honors limit; slack_conversations_unreads returns the documented shape (total_unread_conversations + per-conversation entries) instead of a raw counts dump, with DM display names resolved concurrently.
• Token extraction robustness — LevelDB extraction now returns the newest token instead of the oldest (fixes stale-token invalid_auth after re-login); Chrome cookie snapshots include the -wal/-shm sidecars so extraction works while Chrome is running; extraction temp directories are removed instead of leaking.
• Workflow store safety — a corrupt profile store is quarantined aside (.corrupt-<timestamp>) with a warning instead of being silently replaced on the next save; saves are atomic (temp file + rename).
• Status widget hardening — remote /status fields render as text nodes; docs links are validated https:// URLs.
• conversations.history only sets inclusive when a boundary timestamp is provided; empty user-search queries are rejected instead of matching everyone.