dc88da0bee
Task 20 of the slice plan. Thin wrapper over the repo's intent methods that adds two preconditions: setIntent rejects empty trimmed text, both methods throw "note not found" when the note id doesn't exist. Repo-level COALESCE on intent_prompted_at preserves the first-prompt invariant (spec §3.3); IntentService's job is just input guarding so the IPC handler stays a one-liner. Verification: `npx vitest run tests/unit/IntentService.test.ts` 4 passed. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>