fix(server): preserve due tasks when time formatting changes

[CouchRiv]

What Changed

Fixed-time schedules now compare parsed hours and minutes, so saving 09:00 instead of 9:00 preserves the pending occurrence.

Why

Both formats are accepted by the schedule contract. The current string comparison treats them as a schedule change and recalculates the next run. If today's occurrence is already due but has not dispatched, that save can postpone it until tomorrow.

This targets the V2 branch in #2829. It reuses the existing time parser and leaves actual hour, minute, weekday and interval changes distinct.

Validation

• Four new regression cases fail before the fix; all 14 focused scheduler and contract tests pass afterward.
• The service test uses real input decoding, in-memory SQLite and a controlled clock. It verifies the preserved persisted deadline and that changing the time to 09:30 still reschedules.
• Server typecheck and targeted lint, formatting and diff checks pass. Typecheck reports Effect suggestions outside the changed files.

Checklist

• This PR is small and focused
• I explained what changed and why

Implemented and verified with GPT-6 in the Codex harness.

[macroscopeapp]

Approvability

Verdict: Would Approve

Macroscope's review found this PR approvable — The production change narrowly fixes equality for equivalent fixed-time schedule formats, preventing an otherwise unnecessary save from postponing a pending run. It leaves actual schedule changes and interval behavior intact and includes focused regression coverage.

Not approved because:

• Monthly spending limit reached (workspace setting). Approvability relies on correctness review in order to determine eligibility

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