fix(web): send symbolic comparator values for service alert rules

[dviejokfs]

Summary

• The "Add Alert Rule" dialog on a service's monitoring page (ServiceMonitoring.tsx) sent comparator values gt/gte/lt/lte, but POST /external-services/{id}/metrics/alert-rules only ever accepts the symbolic operators >, <, >=, <= — matching the OpenAPI spec, the monitoring_alert_rules DB CHECK constraint, and the default seed rules. Every submission from that form was rejected with 400 Bad Request: comparator must be one of: >, <, >=, <=.
• Root cause: this page calls the older external-services alert-rules API, but its comparator options were apparently copied from a different, newer alerts API (OTel detectors) that does use text-form values — the two APIs have different contracts and this form used the wrong one.
• Fix: extracted the comparator type/options into web/src/lib/service-alert-comparator.ts (symbolic values matching the actual endpoint), updated ServiceMonitoring.tsx to use it, and added a regression test (service-alert-comparator.test.ts) asserting the options never drift from the backend's accepted set again.
• No backend changes — the Rust handler, DB constraint, and OpenAPI spec were already correct.

Test plan

• bun test src — all 460 existing frontend tests + 2 new ones pass.
• bunx tsc --noEmit — clean.
• Reproduced the original bug directly against a local server: comparator: "gt" → 400.
• Confirmed the fixed frontend's value succeeds against the same unmodified backend: comparator: ">" → 201.
• Full browser walkthrough: logged into a local dev instance, created a Postgres external service, opened its monitoring page, filled out "Add Alert Rule" (comparator dropdown now shows > greater than, ≥ greater or equal, < less than, ≤ less or equal), submitted, and got a 201 response plus an "Alert rule created" success toast, with the new rule appearing in the alert rules table.

[github-actions]

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## [Unreleased]

### Fixed

- **web:** Send symbolic comparator values for service alert rules

### Testing

- **web:** Assert exact comparator option set, not a subset

[greptile-apps]

Greptile Summary

The PR updates service alert-rule submissions to use the symbolic comparator values required by the external-services API.

• Extracts the service-alert comparator type and display options into a shared module.
• Updates the monitoring dialog to submit symbolic operators.
• Strengthens regression coverage by checking exact option membership and duplicate values.

Confidence Score: 5/5

The PR appears safe to merge.

No blocking failure remains.

Important Files Changed

Filename	Overview
web/src/lib/service-alert-comparator.ts	Defines the four symbolic comparator values and their UI labels in a shared typed constant.
web/src/lib/service-alert-comparator.test.ts	Verifies exact comparator membership and rejects duplicate option values.
web/src/pages/ServiceMonitoring.tsx	Uses the shared symbolic comparator contract when rendering and submitting alert rules.

_{Reviews (2): Last reviewed commit: "test(web): assert exact comparator optio..." | Re-trigger Greptile}

[greptile-apps]

Tests are not colocated

This standalone test file separates the comparator contract tests from service-alert-comparator.ts, contrary to the repository requirement that tests remain in the same file as the code they exercise.

Context Used: CLAUDE.md (source)

Note: If this suggestion doesn't match your team's coding style, reply to this and let me know. I'll remember it for next time!

[dviejokfs]

Keeping this as a separate file rather than merging — every other module in web/src/lib/ (password-policy.ts, drop-archive.ts, etc.) follows the same convention: implementation + a colocated but separate *.test.ts. The CLAUDE.md "same file" rule reads as the Rust convention (#[cfg(test)] mod tests inline); there's no precedent anywhere in web/ for TS tests living inside the implementation file itself, so I don't think this is a real deviation.

[greptile-apps]

You're right — this is a false positive. The repository-wide “same file” guidance reflects the Rust #[cfg(test)] convention, while the established TypeScript convention in web/src/lib/ is a separate colocated *.test.ts file. Keeping service-alert-comparator.test.ts separate is consistent with the surrounding modules, so no change is needed.