Status feature file conventions: extensionless imports, .ts for JSX-free modules, test colocation

[kylebernhardy]

Mechanical conventions drift, unique to src/features/instance/status/:

• ~400 extensionful relative imports (from './tabs/DatabaseTab.tsx') — every other feature uses extensionless imports (zero occurrences elsewhere).
• .tsx on JSX-free modules: pipeline/derived/error-rate.tsx, derived/transaction-log-growth.tsx (pure recompute + spec objects) — the top-level pure-spec files correctly use .ts.
• Test layout: the repo convention is colocated *.test.tsx (130 files); status mixes that with a large __tests__/__fixtures__ tree found nowhere else in src/features. Decide one way (probably colocate going forward; wholesale moves optional).
• Registry key naming: pipeline/index.ts:74 'response_200' is the only snake_case key among 22 kebab-case keys. If it must match Harper's wire name, comment that; otherwise normalize. Also add one-line disambiguating comments on the easily-confused connection (per-path success ratio) vs connections (active sessions) entries.

Filed from a Status tab code review.

Comment generated by kAIle (Claude Fable 5)