fix: focus the right field when a form, popover or menu opens (#25)

## Summary
Whatever opens now puts keyboard focus where you'd type next.

| Opens | Before | Now |
| --- | --- | --- |
| Edit Display Name (Alt+Shift+N / Welcome menu) | focus stayed on the page | name field focused, prefilled with the current name and selected |
| Habit → Edit | stayed on the page | name field focused |
| Goal → comments | stayed on the page | comment field focused |
| Focus summary → edit session | stayed on the page | title field focused |
| Add Tag popover (Alt+Shift+T / click) | stayed on the page | "Create new tag" focused; Esc closes |
| Menu (Alt+M / click) | stayed on the button | first item focused; Esc closes and returns focus to the button |

Already correct and unchanged: Alt+G (goal), Alt+N on To-Dos/Goals/Habits/Tags/Boost, to-do inline edits, habit notes, new tags, dialogs and panels.

## Testing
- Lint, typecheck, unit tests and build pass.
- In the browser: Alt+Shift+N → name field focused with "Alex" selected, Esc closes; Alt+Shift+T → "Create new tag" focused, Esc closes; Alt+M → first menu item focused, Esc closes; Alt+G → goal field focused.

Author: ttncode

src/components/BoostApp.tsx

@@ -77,7 +77,11 @@ function AppShell() {
   const goBack = () => setTab(previousTab);
 
   useNavigationHotkeys(navigateFromCurrent);
-  useHotkey("app.displayName", () => setIsEditingName(true));
+  const openNameEditor = () => {
+    setNewName(displayName);
+    setIsEditingName(true);
+  };
+  useHotkey("app.displayName", openNameEditor);
 
   const saveName = () => {
     const trimmed = newName.trim();
@@ -156,6 +160,8 @@ function AppShell() {
                 type="text"
                 value={newName}
                 onChange={(event) => setNewName(event.target.value)}
+                autoFocus
+                onFocus={(event) => event.currentTarget.select()}
                 placeholder="Enter display name"
                 className="w-full px-4 py-2 bg-gray-800 border border-gray-700 rounded-lg text-white placeholder-gray-500 focus:outline-none focus:ring-2 focus:ring-blue-500 mb-4"
                 onKeyDown={(event) => {
@@ -215,7 +221,7 @@ function AppShell() {
         <TopBar
           displayName={displayName}
           displayTime={formatTodayMinutes(todayMinutes)}
-          onEditDisplayName={() => setIsEditingName(true)}
+          onEditDisplayName={openNameEditor}
           onOpenHistory={() => setTab("history")}
         />
         <BottomNav activeTab={tab} onTabChange={setTab} />

src/components/focus/GoalForm.tsx

@@ -112,16 +112,23 @@ function TagSelector({
   const [allTags, setAllTags] = useState<Tag[]>([]);
   const [isOpen, setIsOpen] = useState(false);
   const [isCreating, setIsCreating] = useState(false);
-  const ref = useOutsideDismiss(isOpen, () => {
+  const createButtonRef = useRef<HTMLButtonElement>(null);
+  const close = () => {
     setIsOpen(false);
     setIsCreating(false);
-  });
+  };
+  const ref = useOutsideDismiss(isOpen, close);
   const addTagCombo = useHotkeyLabel("timer.addTag");
   // The Tags row stays mounted but hidden below the `wide` breakpoint.
   useHotkey("timer.addTag", () => {
     if (ref.current?.getClientRects().length) setIsOpen(true);
   }, isActive);
 
+  // Opening (by click or Alt+Shift+T) puts focus on the first action so the keyboard can carry on.
+  useEffect(() => {
+    if (isOpen && !isCreating) createButtonRef.current?.focus();
+  }, [isOpen, isCreating]);
+
   useEffect(() => {
     if (isOpen) databaseService.getTags().then(setAllTags).catch((error: unknown) => console.error("Failed to load tags:", error));
   }, [isOpen]);
@@ -170,14 +177,20 @@ function TagSelector({
         ) : null}
       </div>
       {isOpen ? (
-        <div className="absolute top-full left-0 mt-2 w-64 bg-gray-800 border border-gray-700 rounded-lg shadow-xl z-50 max-h-80 overflow-y-auto">
+        <div
+          className="absolute top-full left-0 mt-2 w-64 bg-gray-800 border border-gray-700 rounded-lg shadow-xl z-50 max-h-80 overflow-y-auto"
+          onKeyDown={(event) => {
+            if (event.key === "Escape" && !isCreating) close();
+          }}
+        >
           <div className="p-2">
             {isCreating ? (
               <NewTagForm onCreate={create} onCancel={() => setIsCreating(false)} />
             ) : (
               <>
                 <div className="mb-2 flex gap-1">
                   <button
+                    ref={createButtonRef}
                     onClick={() => setIsCreating(true)}
                     className="flex-1 flex items-center gap-2 px-3 py-2 text-sm text-gray-300 hover:bg-gray-700 rounded transition-colors"
                   >

src/components/pages/HistoryPage.tsx

@@ -592,6 +592,7 @@ export function HistoryPage({ userId }: { userId: string }) {
                                     type="text"
                                     value={editGoal}
                                     onChange={(e) => setEditGoal(e.target.value)}
+                                    autoFocus
                                     className="flex-1 bg-gray-800 border border-gray-700 rounded px-2 py-1 text-sm text-white focus:outline-none focus:border-blue-500"
                                     placeholder="Session title"
                                   />

src/components/pages/goals/GoalCard.tsx

@@ -167,6 +167,7 @@ export function GoalCard(props: GoalCardProps) {
                 type="text"
                 value={draft}
                 onChange={(e) => setDraft(e.target.value)}
+                autoFocus
                 onKeyDown={(e) => {
                   if (e.key === "Enter" && !e.shiftKey) {
                     e.preventDefault();

src/components/pages/habits/HabitCard.tsx

@@ -48,7 +48,7 @@ function EditForm({ habit, onSave, onCancel }: { habit: Habit; onSave(edit: Habi
     <div className="mb-4 space-y-4">
       <div>
         <FieldLabel>Habit Name</FieldLabel>
-        <input type="text" value={name} onChange={(e) => setName(e.target.value)} className={FIELD_INPUT} />
+        <input type="text" value={name} onChange={(e) => setName(e.target.value)} autoFocus className={FIELD_INPUT} />
       </div>
       <div>
         <FieldLabel>Description (Optional)</FieldLabel>

src/components/shell/StartMenu.tsx

@@ -56,6 +56,8 @@ export function StartMenu({ onNavigate }: { onNavigate(tab: Tab): void }) {
   const [isSettingsOpen, setIsSettingsOpen] = useState(true);
   const [isSoundsOpen, setIsSoundsOpen] = useState(false);
   const menuRef = useRef<HTMLDivElement>(null);
+  const panelRef = useRef<HTMLDivElement>(null);
+  const toggleRef = useRef<HTMLButtonElement>(null);
   const isMobile = useMediaQuery(MOBILE_QUERY);
   // In the 400x600 popup a floating bottom-left button would cover the timer controls,
   // so the menu moves into the top bar and opens downward.
@@ -65,6 +67,10 @@ export function StartMenu({ onNavigate }: { onNavigate(tab: Tab): void }) {
   const fullPageCombo = useHotkeyLabel("app.fullPage");
   useHotkey("app.fullPage", () => void openFullPage(), isPopup);
 
+  useEffect(() => {
+    if (isOpen) panelRef.current?.querySelector("button")?.focus();
+  }, [isOpen]);
+
   useEffect(() => {
     if (!isOpen) return;
     const closeOnOutsideClick = (event: MouseEvent) => {
@@ -92,7 +98,15 @@ export function StartMenu({ onNavigate }: { onNavigate(tab: Tab): void }) {
             isPopup ? "top-full right-0 mt-2" : "bottom-full left-0 mb-2"
           }`}
         >
-          <div className="py-2 max-h-[70vh] overflow-y-auto force-scrollbar">
+          <div
+            ref={panelRef}
+            className="py-2 max-h-[70vh] overflow-y-auto force-scrollbar"
+            onKeyDown={(event) => {
+              if (event.key !== "Escape") return;
+              setIsOpen(false);
+              toggleRef.current?.focus();
+            }}
+          >
             {isPopup ? (
               <button onClick={() => void openFullPage()} className={TOP_ITEM}>
                 <Expand className="w-5 h-5" />
@@ -132,6 +146,7 @@ export function StartMenu({ onNavigate }: { onNavigate(tab: Tab): void }) {
         </div>
       ) : null}
       <button
+        ref={toggleRef}
         onClick={() => setIsOpen(!isOpen)}
         aria-label="Menu"
         title={menuCombo ? `Menu (${menuCombo})` : "Menu"}