Phase 9: homebrew content + packs

- Homebrew entity (monster/spell/item/feat/condition) — Dexie v6, repo, hook,
  cascade-deleted with campaign
- Homebrew editor page: per-kind fields + description, create/edit/delete
- Compendium merges campaign homebrew of the matching kind (HB badge, generic
  HomebrewDetail) with the same cross-links (add monster->combat, spell/item->character)
- Content packs: export/import homebrew as JSON (validated, ids reassigned)
- System extensibility documented via the existing RulesSystem registry seam
- Fix: card editors (homebrew/npc/quest/note) debounce-save the FULL snapshot, not
  partial patches — editing two fields fast no longer drops an edit

New homebrew e2e + cascade test coverage.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/features/world/NotesPage.tsx

@@ -99,7 +99,16 @@ function NoteEditor({
   const [body, setBody] = useState(note.body);
   const [tags, setTags] = useState(note.tags.join(', '));
 
-  const save = useDebouncedCallback((patch: Partial<Note>) => void notesRepo.update(note.id, patch), 350);
+  // Save the full snapshot so editing title + body quickly doesn't drop an edit.
+  const save = useDebouncedCallback((next: { title: string; body: string; tags: string }) => {
+    void notesRepo.update(note.id, {
+      title: next.title,
+      body: next.body,
+      tags: next.tags.split(',').map((t) => t.trim()).filter(Boolean),
+    });
+  }, 350);
+  const persist = (over: Partial<{ title: string; body: string; tags: string }>) =>
+    save({ title, body, tags, ...over });
 
   const backlinks = allNotes.filter(
     (n) => n.id !== note.id && extractWikiLinks(n.body).some((t) => t.toLowerCase() === note.title.toLowerCase()),
@@ -113,7 +122,7 @@ function NoteEditor({
           className="font-display text-lg font-semibold"
           value={title}
           aria-label="Note title"
-          onChange={(e) => { setTitle(e.target.value); save({ title: e.target.value }); }}
+          onChange={(e) => { setTitle(e.target.value); persist({ title: e.target.value }); }}
         />
         <Button
           variant="ghost"
@@ -128,17 +137,14 @@ function NoteEditor({
         Tags (comma-separated)
         <Input
           value={tags}
-          onChange={(e) => {
-            setTags(e.target.value);
-            save({ tags: e.target.value.split(',').map((t) => t.trim()).filter(Boolean) });
-          }}
+          onChange={(e) => { setTags(e.target.value); persist({ tags: e.target.value }); }}
           placeholder="lore, barovia, npc"
         />
       </label>
 
       <textarea
         value={body}
-        onChange={(e) => { setBody(e.target.value); save({ body: e.target.value }); }}
+        onChange={(e) => { setBody(e.target.value); persist({ body: e.target.value }); }}
         placeholder="Write here… link other notes with [[Note Title]]."
         className="min-h-48 w-full resize-y rounded-md border border-line bg-surface px-3 py-2 text-sm text-ink focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-accent/60"
       />