refactor(hooks): burn down the 35 compiler-era react-hooks findings, rules bind as errors

[catomean]

Burn-down for the five compiler-era react-hooks rules that PR #451 downgraded to "warn". All 35 findings are restructured, the warn-downgrade block in eslint.config.mjs is deleted (as its own comment instructed), and the rules now bind at error severity — verified by mutation probe (a violating scratch component fails lint with exit 1). The settings.react.version pin stays.

Per-rule counts

Rule	Before	After
react-hooks/set-state-in-effect	25	0
react-hooks/refs	6	0
react-hooks/purity	1	0
react-hooks/immutability	1	0
react-hooks/preserve-manual-memoization	2	0
Total	35	0

Notable restructures

set-state-in-effect — three recipes, chosen per call site:

• Guarded render-time adjustments (React's "adjusting state when props change" pattern) replace prop/URL→state mirror effects: ProjectAutopilotToggle, ZellijLivePanel, LiveUrlField, ProjectWorkspaceHeader, ProjectCard (capacity re-arm + run-transition dismiss reset), ControlPanel selection reconciliation, CommandPalette open-reset, LokiWorkspace (?q= prefill, selection seed, transcript switch), use-auto-continue, use-poll, use-project-card-actions. Same commit semantics, one paint earlier.
• Pure fetch cores + event wrappers: async loaders called from mount effects now keep every setState inside promise callbacks (.then/.catch/.finally); thin wrappers prime spinners for buttons/timers. ActivityTimeline, PeekTabDrawer (fetchRemotePeek returns the content instead of applying it), PeopleBookPanel, LokiWorkspace reloads, use-control-data (fetchControl core + refresh(manual) wrapper).
• Lazy initializers / real events: CommandPalette recents hydrate from sessionStorage in the useState initializer; BillingSettings seeds the ?billing= notice the same way; MermaidDiagram's matchMedia mirror became useSyncExternalStore; LogConversationButton clears results in the input's onChange.

refs: ProjectOperationsView's frozen row order moved from a ref-inside-useMemo to state adjusted during render behind the same setKey guard (row-freeze semantics preserved). queue-list's editRef plumbing is deleted — the edit textarea mounts with autoFocus. TerminalView's fontOverrideRef is mirrored via an effect, matching the file's existing onLive/onGeometry pattern.

purity: ProjectCard now receives nowS from ControlPanel's per-render clock via buildCardProps instead of calling Date.now() in render — the card's staleness math uses the same clock as the snapshots it renders.

immutability: BillingSettings navigates to Stripe Checkout via window.location.assign() instead of assigning location.href.

preserve-manual-memoization: TerminalSurface.switchAgent and AskLokiButton.ask captured whole context objects while declaring narrowed deps; the needed field (tabDir / workspaceKey) is now a local, so the manual deps match what the compiler infers.

Justified per-line disables (2)

• ProjectCard.tsx auto-reroute effect — episodic automation reacting to polled session state with ref-tracked loop guards (once per capacity episode); deriving that state during render would rewire the loop-safety of a live agent-switching path.
• ControlPanel.tsx ?focus= deep-link effect — App Router param changes only surface as re-renders, so this effect is the event handler; it resolves the target once, atomically, then selects + highlights + scrolls + clears the params. Splitting it would resolve the target twice against possibly-different data mid-refresh.

Two unused directives (ready-banner, ShellWorkspace) were removed.

Verification

• npm run lint — 0 errors (3 pre-existing @next/next/no-location-assign-relative-destination warnings untouched); mutation probe confirms the five rules fail the lint at error severity
• npx tsc --noEmit — clean
• npm run test:unit — 124/124
• npm run format:check — clean

🤖 Generated with Claude Code

https://claude.ai/code/session_01WqKqMnHQHSmkGFfc5t7Rxn