Release 0.1.9 channel readiness hardening

[Dkm0315]

Summary

• prepare Muster 0.1.9 point release
• add muster channels ready <channel> as the single-command setup path for channel operators
• harden Slack, Discord, WhatsApp, Google Chat, Teams, and Telegram adapter delivery/auth behavior
• update channel capability packs and integration guidance to point at the single-command ready flow

Channel depth

• Telegram defaults to background long-poll daemon setup; webhook registration is explicit and opt-in
• Slack/WhatsApp retries are idempotent after platform auth, avoiding duplicate replies/token spend
• Discord, GChat, Teams, WhatsApp, Slack, and Telegram adapter retries use delivery ids where available
• GChat and Teams auth failures now return 401 instead of generic server errors

Release

• bump workspace package versions to 0.1.9
• add CHANGELOG.md entry for 0.1.9

Validation

• pnpm --filter @musterhq/gateway test -- --test-name-pattern "slack|whatsapp|gchat|teams|discord|telegram webhook" — 80/80 passed
• pnpm --filter @musterhq/cli test -- --test-name-pattern "channel|gateway|integration" — 56/56 passed
• pnpm --filter @musterhq/core test -- --test-name-pattern "channel packs produce setup plans" — 359/359 passed
• pnpm --filter @musterhq/gateway build — passed
• pnpm --filter @musterhq/cli build — passed

Frappe-2 verification

• deployed the latest CLI build to Frappe-2
• verified muster channels list advertises muster channels ready ...
• verified dry muster channels ready telegram ... --no-start does not force webhook URL and points to background long-poll daemon
• verified dry muster channels ready slack ... --no-start reaches ready state with credentials and blocks honestly without them