feat(services): deterministic async states and retry for dashboard (#626)

[woahwhattheheck]

Closes #626

/claim #626

What changed

• Replaced independent loading/error/rows booleans in services dashboard with one strict discriminated union: loading, empty, error, or success. Rows and pagination cannot appear behind an error or loading screen.
• Added an accessible same-page Retry path, deterministic pagination transitions and ignore-on-cancel for superseded requests.
• Stable SERVICES_FETCH_FAILED typed error with a safe user-facing message; no backend exception leakage.
• Retained sorting, page navigation and ID copy controls. Added polite loading/empty/success announcements and reused the existing accessible ErrorMessage retry control.
• Added focused unit transition and page integration test files including all five specified edge cases and page-change stale row suppression.

Verification

Source and tests are complete; focused tests are authored but were not run here. No broad lint, test suite, or build run. Sponsor CI and maintainer review remain for acceptance.

Compensation

I am the original author and affirmatively request GrantFox OSS / FWC26 contribution, claim, and applicable reward credit. This is a MAYBE REWARDED issue; no dollar amount or payout is claimed as confirmed.

Source base 0d47dba0eb086756a906fc66670f98b2374fce04, PR head a3e683347747ed5f38180d363ed07566d0b5ffcf.