Improve Mantis CLI, dashboard, and edge recovery flows

[adamXbot]

Summary

Fixes the CLI, server dashboard, and edge experience issues found in the app-wide audit:

• Shows generated installer snippets after mantis new --install, and includes the created key ID when later setup fails.
• Creates keys and notification destinations in one database transaction; destination edits preserve unchanged destination IDs and secrets.
• Adds destination editing and Home Assistant creation to the dashboard.
• Adds dashboard key search and pagination, and refreshes hit delivery states in the live feed.
• Uses stable timestamp-and-ID hit cursors so CLI follow can page through bursts without skipping hits.
• Accepts the configured edge trigger response status in --test and returns a failing exit status when the test fails.

Verification

• Root tests: 300 passed (with loopback access for health probe tests)
• CLI tests: 148 passed (TERM=xterm-256color for Unicode rendering tests)
• Edge tests: 64 passed
• Root, CLI, and edge TypeScript checks passed
• Next.js production build passed with build-only environment values
• Database integration tests and authenticated UI inspection could not run: no local Postgres or Docker socket is available