feat: inline entry title renaming (#14)

* feat: inline entry title renaming

- database.rs: add update_entry_title(conn, entry_uid, title) -> Result<bool>
  targets archived_entries table; returns false for unknown uid
- routes.rs: PATCH /api/archives/:archive_id/entries/:entry_uid (ROLE_USER)
  maps false -> 404; 3 tests (401 unauthed, 204+persists, 404 unknown uid)
- api.js: updateEntryTitle(archiveId, entryUid, title)
- ContextRail.jsx: click title h2 -> inline input; Enter/blur commits,
  Escape cancels (cancel ref prevents double-save on blur after Escape);
  pencil icon fades in on hover as edit affordance
- App.jsx: handleEntryTitleChange mutates entries + selectedEntry in-place
- styles.css: rail-title--editable cursor/hover, pencil icon show/hide,
  rail-title-input underline style
- rebuild frontend bundle

* chore: remove + prefix from Capture button label

frontend/src/App.jsx

@@ -178,6 +178,15 @@ export default function App() {
     if (archiveId) fetchTags(archiveId).then(setTagNodes)
   }, [archiveId])
 
+  const handleEntryTitleChange = useCallback((entryUid, newTitle) => {
+    setEntries(prev => prev.map(e =>
+      e.entry_uid === entryUid ? { ...e, title: newTitle } : e
+    ))
+    setSelectedEntry(prev =>
+      prev && prev.entry_uid === entryUid ? { ...prev, title: newTitle } : prev
+    )
+  }, [])
+
   const handleCaptureClick = useCallback(() => {
     setCaptureDialogOpen(true)
   }, [])
@@ -277,6 +286,7 @@ export default function App() {
             onTagFilterSet={handleTagFilterSet}
             tagNodes={tagNodes}
             onTagsRefresh={handleTagsRefresh}
+            onEntryTitleChange={handleEntryTitleChange}
           />
         </main>
         <CaptureDialog