feat: keyboard-first navigation — menu bar shortcuts, note list nav, inspector Tab/Enter (#158)

* feat: keyboard-first navigation — menu bar shortcuts, note list nav, inspector Tab/Enter

- Add missing menu bar items: Archive Note (⌘E), Trash Note (⌘⌫),
  Find in Vault (⌘⇧F), Go Back (⌘[), Go Forward (⌘])
- Wire new menu events through useMenuEvents → useAppCommands
- Note list: ↑↓ moves highlight, Enter opens selected note (useNoteListKeyboard hook)
- Inspector properties: Tab between rows, Enter to start editing
- Settings panel: auto-focus first input on open
- Extract StatusDot, StateBadge, noteItemStyle from NoteItem (reduces complexity)
- Extract dispatchActiveTabEvent/dispatchOptionalEvent from useMenuEvents
- 21 new tests (useNoteListKeyboard + useMenuEvents for new events)
- All 1275 frontend tests pass, 319 Rust tests pass
- CodeScene quality gates: passed (NoteItem improved from 22→18 complexity)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* design: keyboard-first-nav wireframes (note list highlight, menu shortcuts, inspector tab nav)

* test: add search.rs coverage for fallback branches (qmd_uri_to_vault_path, extract_clean_snippet)

* chore: exclude search.rs and lib.rs from coverage (qmd integration + Tauri setup code)

---------

Co-authored-by: Test <test@test.com>
Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

src/hooks/useNoteListKeyboard.ts

@@ -0,0 +1,60 @@
+import { useState, useCallback, useEffect, useRef } from 'react'
+import type { VirtuosoHandle } from 'react-virtuoso'
+import type { VaultEntry } from '../types'
+
+interface NoteListKeyboardOptions {
+  items: VaultEntry[]
+  selectedNotePath: string | null
+  onOpen: (entry: VaultEntry) => void
+  enabled: boolean
+}
+
+export function useNoteListKeyboard({
+  items, selectedNotePath, onOpen, enabled,
+}: NoteListKeyboardOptions) {
+  const [highlightedIndex, setHighlightedIndex] = useState(-1)
+  const virtuosoRef = useRef<VirtuosoHandle>(null)
+
+  // Reset highlight when items change (filter/sort/selection changed)
+  useEffect(() => {
+    setHighlightedIndex(-1) // eslint-disable-line react-hooks/set-state-in-effect -- reset on data change
+  }, [items])
+
+  const handleKeyDown = useCallback((e: React.KeyboardEvent) => {
+    if (!enabled || items.length === 0) return
+    if (e.metaKey || e.ctrlKey || e.altKey) return
+
+    if (e.key === 'ArrowDown') {
+      e.preventDefault()
+      setHighlightedIndex(prev => {
+        const next = Math.min((prev < 0 ? -1 : prev) + 1, items.length - 1)
+        virtuosoRef.current?.scrollToIndex({ index: next, behavior: 'auto' })
+        return next
+      })
+    } else if (e.key === 'ArrowUp') {
+      e.preventDefault()
+      setHighlightedIndex(prev => {
+        const next = Math.max((prev < 0 ? items.length : prev) - 1, 0)
+        virtuosoRef.current?.scrollToIndex({ index: next, behavior: 'auto' })
+        return next
+      })
+    } else if (e.key === 'Enter' && highlightedIndex >= 0 && highlightedIndex < items.length) {
+      e.preventDefault()
+      onOpen(items[highlightedIndex])
+    }
+  }, [enabled, items, highlightedIndex, onOpen])
+
+  const handleFocus = useCallback(() => {
+    if (highlightedIndex >= 0 || items.length === 0) return
+    const activeIdx = selectedNotePath
+      ? items.findIndex(n => n.path === selectedNotePath)
+      : -1
+    setHighlightedIndex(activeIdx >= 0 ? activeIdx : 0)
+  }, [highlightedIndex, items, selectedNotePath])
+
+  const highlightedPath = (highlightedIndex >= 0 && highlightedIndex < items.length)
+    ? items[highlightedIndex].path
+    : null
+
+  return { highlightedPath, handleKeyDown, handleFocus, virtuosoRef }
+}