Phase 2: document CRUD + auto-save

Backend internal/docs: chi sub-router (list/create/get/update/delete)
mounted at /api/docs, scoped to the local user. Create uses RETURNING;
update is a COALESCE partial-update so rename and full editor save share
one PUT. JSON 404/400 errors; handlers_test.go walks the lifecycle.

Frontend: api/client.ts, useAutoSave (1.5s debounce + saveNow flush
before doc switch), EditorCore (Tiptap StarterKit/Underline/TextAlign/
Placeholder/CharacterCount) + Toolbar, DocList/DocListItem, StatusBar,
and an App.tsx that orchestrates load/select/create/delete with
optimistic sidebar patching. content + content_text + word_count are
emitted together on every edit. .petal-prose styling (Lora body, Nunito
headings).

Verified: tsc clean, vite build, go build, full CRUD smoke test incl.
CJK title round-trip and SPA serve.

Claude-Session: https://claude.ai/code/session_016Yr6jELuRc7hyzYLccQKZd

web/src/components/DocList/DocList.tsx

@@ -0,0 +1,49 @@
+import type { DocSummary } from '../../api/client'
+import { DocListItem } from './DocListItem'
+
+interface Props {
+  docs: DocSummary[]
+  selectedId: string | null
+  onSelect: (id: string) => void
+  onCreate: () => void
+  onDelete: (id: string) => void
+}
+
+// DocList is the 260px sidebar: the document browser plus a New button.
+export function DocList({ docs, selectedId, onSelect, onCreate, onDelete }: Props) {
+  return (
+    <aside
+      className="flex w-[260px] shrink-0 flex-col gap-2 p-3"
+      style={{ borderRight: '1px solid var(--color-border)' }}
+    >
+      <button
+        type="button"
+        onClick={onCreate}
+        className="flex items-center justify-center gap-2 py-2.5 text-sm font-bold text-white"
+        style={{ borderRadius: 'var(--radius-pill)', background: 'var(--color-accent)' }}
+        onMouseEnter={(e) => (e.currentTarget.style.background = 'var(--color-accent-hover)')}
+        onMouseLeave={(e) => (e.currentTarget.style.background = 'var(--color-accent)')}
+      >
+        <span className="text-base leading-none">＋</span> New Doc
+      </button>
+
+      <div className="flex flex-1 flex-col gap-0.5 overflow-y-auto">
+        {docs.length === 0 ? (
+          <p className="px-3 py-6 text-center text-xs" style={{ color: 'var(--color-muted)' }}>
+            No documents yet.
+          </p>
+        ) : (
+          docs.map((doc) => (
+            <DocListItem
+              key={doc.id}
+              doc={doc}
+              active={doc.id === selectedId}
+              onSelect={() => onSelect(doc.id)}
+              onDelete={() => onDelete(doc.id)}
+            />
+          ))
+        )}
+      </div>
+    </aside>
+  )
+}