fix(server): skip disabled settlement lookups

[yashranaway]

What Changed

Check settlement settings before reading the shell snapshot or preparing candidates. Disabled timer and merge sweeps perform no snapshot or pull-request lookup work.

The final decision still reads fresh settings so disabling settlement during a lookup prevents a stale decision. Re-enabling the setting resumes settlement.

Why

Automatic settlement looks up candidate pull requests even when both settings are disabled, spawning Git and provider processes on each scheduled sweep.

Fixes #9714.

Testing

• ThreadSettlementReactor.test.ts passes, 12/12, covering disabled timer and merge sweeps and re-enabling settlement.
• Server typecheck, targeted lint, and formatting pass.

Checklist

• One focused change
• Explained what changed and why
• Added regression coverage for the changed behavior
• No UI layout or animation changes

Model: GPT-6 Astra
Harness: T3 code

Note

Skip settlement work in ThreadSettlementReactor.sweep when both triggers disabled

• The sweep method now reads server settings before loading the shell snapshot and returns immediately when merge-based settlement is disabled and the day-based interval is unset
• Test harness makeThreadSettlementHarness records settings-service reads so tests can observe and assert on settings access
• Adds a test verifying that startup, activation, timer, and merge sweeps perform no snapshot, pull-request, invalidation, or command work while both automatic-settlement settings are disabled, then resume after one is enabled
• Behavioral Change: a disabled sweep now exits before the snapshot load, so existing tests that expected snapshot or lookup work during disabled sweeps have updated count expectations in ThreadSettlementReactor.test.ts

^{Macroscope summarized 68a4096.}

[macroscopeapp]

Approvability

Verdict: Approved at 68a4096

Macroscope's review found this PR approvable — This is a focused server bug fix that avoids snapshot, Git, and pull-request lookups when both existing settlement options are disabled, while preserving enabled behavior. Regression tests cover startup, timer, merge, and re-enabling scenarios, and product defaults remain unchanged.

^{You can add or adjust custom eligibility rules. Learn more.}

[t3dotgg]

Note

🤖 Claude Fable 5.1 responding on behalf of Theo

Rebased onto main as #10424 so this can land for the stable release. #10103 changed the same sweep function and test file, and my token could not push the rebase to your fork. Your commit and authorship are preserved. Only change: the rebased test asserts on dispatched commands instead of lookup counts, because inactive threads now settle without a PR lookup. Closing this in favor of #10424.