Adopt eslint-plugin-react-hooks v7 React-Compiler rules (deferred in #1062)

[xiaolai]

Context

PR #1062 upgraded eslint-plugin-react-hooks 5 → 7. v7 folds the React Compiler rule set into recommended, which flags 67 pre-existing sites. Adopting these is a deliberate, codebase-wide refactor — not a dependency bump — so they were deferred in eslint.config.js (with an inline comment) to preserve the prior enforcement level and keep the upgrade green.

This issue tracks turning them back on, incrementally.

Deferred rules (currently off in eslint.config.js)

Rule	Sites	What it catches
react-hooks/set-state-in-effect	33	setState called synchronously in an effect body (cascading renders)
react-hooks/refs	31	reading/writing refs during render
react-hooks/preserve-manual-memoization	3	manual useMemo/useCallback the compiler can't preserve
react-hooks/immutability	1	mutating values that should be immutable

Also: react-hooks/exhaustive-deps is pinned to warn (its historical level under v5) — v7 raised it to error.

Suggested approach

Adopt one rule at a time, file-scoped:

1. Flip a rule from off → error in eslint.config.js.
2. pnpm lint to list the violations.
3. Fix each (many set-state-in-effect cases are legitimate and need a real refactor or a scoped // eslint-disable-next-line with a reason — don't blanket-disable).
4. Repeat per rule. Remove the deferral comment once all four are back on.

Lowest-risk first: immutability (1), preserve-manual-memoization (3), then refs (31), then set-state-in-effect (33).

Source: the inline rationale block in eslint.config.js is the authoritative record.