Rackpad 1.8.7-beta.0

This candidate combines notification retries and ntfy publishing with MCP token,
collector host-networking and hover-detail fixes. Source changes do not establish
that an image or GitHub Release has been published.

Changes to test

• MCP tokens leave the active list when revoked, retain labelled history, and
  can be created again. Proposal-loading failures no longer block token refresh.
• Proxmox and Hyper-V collector JSON stages host management IPs and selected
  adapters. Reimports preserve port IDs, connector choices and cable links;
  conflicts and per-adapter failures are reported.
• Ordered hover details include passive-device type and rack/U placement.
  Personal field preferences, including optional specs, apply across canvases.
• Production Docker stages use patched Node 22.23.4, and candidate smoke verifies
  the actual runtime. Native deployments must update Node separately.
• Notifications retain every channel result. Any successful channel counts as
  delivery; failed channels are reported without resending to successful ones.
  Total failures remain pending across restart and are retried through monitor
  checks no faster than the greater of 60 seconds or the monitor interval.
• New online/offline transitions supersede pending events. Unknown observations
  postpone delivery; disabling notifications or a category clears its pending
  events. Only successful delivery advances the last-alert timestamp.
• ntfy accepts a complete topic URL and optional encrypted, write-only access
  token. Token-bearing requests require HTTPS. Redirects and embedded URL
  credentials are refused; network checks and certificate verification remain.
• Built-in templates can be duplicated repeatedly into independently named
  custom copies. Original templates and applied device snapshots stay intact.
• Existing beta service links and TCP/UDP endpoint documentation remain included.
  Production-image smoke coverage adds the actual schema-55 stable baseline,
  service relationships, endpoint writes, restart persistence and paired rollback.

See services and alerts and the
template guide.

Upgrade and rollback

Schema is 57. Schema 56 adds optional service network endpoints; migration 57
adds nullable pending-notification kind, event time and last-attempt time to
monitors. Existing rows acquire no historical pending events. Logical/native
backups preserve pending delivery state; older backups default it to empty.

Portable JSON exports redact ntfy credentials; re-enter the token after restore.
Native snapshots preserve the encrypted token and require the matching
RACKPAD_SECRET_KEY. Keep the previous image with a consistent pre-upgrade
database/configuration/key snapshot. Rollback restores that complete pair; never
attach older binaries to the migrated database or rely on automatic refusal.

Acceptance and publication

Run the standard/full gates, Chromium/Firefox acceptance, storage compatibility,
Linux custom-user storage checks and immutable AMD64/ARM64 image smoke tests.
Use only the image digest associated with the exact successful revision.
No new environment variable, listener, public route or deployment privilege is
introduced. SMTP-provider acceptance for #199, template/service reporter feedback,
#164 editor acceptance and #184 Ubuntu confirmation remain separate requirements.