Fix task side effects after direct file edits

[martin-forge]

Summary

Fixes #1921.

• Registers reconciliation on TaskNotes' existing file-updated emitter after lazy calendar service initialization.
• Persists calendar-relevant task fingerprints in plugin data so external markdown/frontmatter edits can be compared to the last synced state.
• Routes changed linked tasks through existing Google Calendar update behavior, and creates eligible unlinked tasks when create-on-sync is enabled.
• Reconciles external status transitions with the existing auto-archive service by scheduling or cancelling queued auto-archives from the current status config.
• Baselines missing startup fingerprints without Google Calendar API writes or auto-archive scheduling to avoid first-run bulk side effects.

Related to #1696 and #1924. This PR is intentionally scoped to direct task-file reconciliation; moved-recurring exception support is separate.

Tests

• npm test -- --runInBand tests/services/TaskCalendarSyncService.test.ts tests/unit/issues/issue-google-calendar-external-file-reconciliation.test.ts
• npm run typecheck
• npm run lint
• npm run build
• vault-python 7 System/Scripts/vault/scan_public_pr.py --repo /Users/martin/Developer/tasknotes-main --base origin/main --head martin-forge/issue-1921-external-calendar-reconciliation-standalone