Finish automatic catalog refresh controls

[shiny-code-bot]

Issue #638’s first slice added automatic catalog refresh, but operators still could not configure its cadence or see when catalog/provider attention was needed. Moving the macOS runtime to a newly installed checkout could also strand provider credentials in the previous checkout.

This change adds the catalog refresh interval to Settings, exposes refresh cadence and provider configuration notices in Activity, and carries the existing runtime .env forward atomically when the LaunchAgent moves to a new checkout. The carry-forward fails loudly when an expected source environment is missing or invalid, and leaves an existing target .env untouched.

Validation:

• scripts/pre-commit-check.sh: 1,992 passed, 2 skipped; CLI smoke; Svelte check; lint; 462 frontend tests; build; desktop and 390 px browser route matrix passed
• Focused backend tests: 50 passed with 4 subtests
• Manual browser review covered Settings editing/reset and Activity maintenance notices
• PyCharm inspection reported pre-existing whole-file findings outside the changed hunks; no finding mapped to a changed hunk
• Two later hook reruns reached the empty Movie Library fixture and timed out waiting for its empty-state sentence, while both APIs returned 200 and the title, required copy, and layout checks passed; this route is outside this change

Refs #638