perf(polling): pause background refreshes when hidden

[beruro]

Summary

• centralize recurring frontend backend/status refreshes behind a visibility-aware, sequential polling hook
• abort stale polling episodes before identity-scoped consumers commit React/Jotai state
• share system resource metrics across Settings and Sidebar consumers with request coalescing
• coalesce Browser console/network drain requests and remove obsolete inline-WebView interval plumbing
• consolidate Git watcher health, polling fallback, and recovery into one state-preserving monitor
• add the completed 10-layer architecture audit in docs/architecture-audit-2026-07-16/PollingLifecycle.md

Audit findings resolved

The pre-commit architecture audit found and fixed two blocking race classes:

1. old async polling episodes could write after a dependency/restart-key change
2. Git watcher restart removed RepoState before recreation, which could destroy fallback/retry metadata on failure

The final re-audit verdict is safe to commit / PR.

Verification

• pnpm exec eslint on all 36 changed frontend source/test files
• scoped TypeScript check on all changed frontend files
• pnpm exec vitest run src/hooks/fileReview src/hooks/platform/useInlineWebview/__tests__/useWebviewCommands.test.ts src/modules/WorkStation/Browser/SessionReplay/__tests__/config.test.ts src/scaffold/NavigationSidebar/connectors/WorkstationSidebarConnector/menuSelection.test.ts — 10 tests passed
• cargo fmt --manifest-path crates/git/Cargo.toml --check
• cargo test -p git --lib — 129 tests passed
• cargo clippy -p git --all-targets -- -D warnings
• git diff --check
• pre-commit hooks: lint-staged, scoped TypeScript, and scoped Git Clippy passed

Scope notes

• This is a stacked PR based on feat(hermes): add native lifecycle hooks for Hermes #386 (junyu/hermes-hook-status) because several touched polling consumers were changed on that branch.
• It intentionally excludes unrelated updater UX/i18n, imported-history, key-vault, chat-history, and task-kanban work present in the source worktree.
• It intentionally excludes useDataSourceAutoScan; an independent focus-adaptive implementation landed on develop as 5be17525b while this audit was running.

Dependency

• feat(hermes): add native lifecycle hooks for Hermes #386 merged first; then retarget this PR to develop if GitHub does not update the base automatically.