- lib/services/personal-channels.ts: isValidTeamsWebhookUrl, isValidNtfyTopic,
mintNtfyTopic, sendChannelTest, TEST_MESSAGE_BODY, isPersonalChannelType,
PERSONAL_CHANNEL_TYPES
- GET /api/me/channels: returns user's personal channels (owner_user_id scoped)
- PUT /api/me/channels/[type]: WITH-CTE UPSERT + best-effort test send
- DELETE /api/me/channels/[type]: removes user's channel, 404 if missing
- POST /api/me/channels/[type]/test: re-sends test to existing channel
- SSRF mitigation via Teams URL hostname allowlist (T-09-02-06)
- Race window closed by partial unique index from Plan 01 (T-09-02-10)
