feat: objects table with M2M words/pictures/pairs

- objects: status enum, JSONB selections, notes, blocked_topic, auto-timestamps
- pairs placeholder table for future use
- Junction tables: object_words, object_pictures, object_pairs
- Full CRUD + link/unlink endpoints for all three relations
- README updated

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

README.md

@@ -136,6 +136,47 @@ words ──────────── word_pictures ───────
 | `created_at` | `TIMESTAMPTZ` | `NOW()` | Auto-set on insert |
 | `updated_at` | `TIMESTAMPTZ` | `NOW()` | Auto-updated on every change (trigger) |
 
+### Table: `objects`
+
+| Column | Type | Default | Description |
+|---|---|---|---|
+| `id` | `UUID` | `gen_random_uuid()` | Primary key |
+| `status` | `VARCHAR(20)` | `draft` | `draft` · `blocked` · `published` |
+| `selections` | `JSONB` | `null` | Frei strukturierter JSON-Block |
+| `notes` | `TEXT` | `null` | Notizen |
+| `blocked_topic` | `TEXT` | `null` | Grund/Thema der Blockierung |
+| `published_at` | `TIMESTAMPTZ` | `null` | Auto-set when status → `published` |
+| `blocked_at` | `TIMESTAMPTZ` | `null` | Auto-set when status → `blocked` |
+| `created_at` | `TIMESTAMPTZ` | `NOW()` | Auto-set on insert |
+| `updated_at` | `TIMESTAMPTZ` | `NOW()` | Auto-updated on every change (trigger) |
+
+**Relations:** M2M mit `words`, `pictures`, `pairs` (pairs folgt später)
+
+### Table: `pairs` (Platzhalter — Felder folgen)
+| Column | Type |
+|---|---|
+| `id` | `UUID` PK |
+| `created_at` | `TIMESTAMPTZ` |
+| `updated_at` | `TIMESTAMPTZ` |
+
+### Table: `object_words` (Junction)
+| Column | Type |
+|---|---|
+| `object_id` | `UUID` FK → `objects.id` CASCADE |
+| `word_id` | `UUID` FK → `words.id` CASCADE |
+
+### Table: `object_pictures` (Junction)
+| Column | Type |
+|---|---|
+| `object_id` | `UUID` FK → `objects.id` CASCADE |
+| `picture_id` | `UUID` FK → `pictures.id` CASCADE |
+
+### Table: `object_pairs` (Junction)
+| Column | Type |
+|---|---|
+| `object_id` | `UUID` FK → `objects.id` CASCADE |
+| `pair_id` | `UUID` FK → `pairs.id` CASCADE |
+
 ### Table: `word_categories` (Junction)
 | Column | Type |
 |---|---|
@@ -306,6 +347,46 @@ curl -X POST "$BASE/api/categories" \
 
 ---
 
+### Objects
+
+#### `GET /api/objects` — Liste (`?status=draft&limit=50&offset=0`)
+#### `GET /api/objects/:id` — Einzelnes Object inkl. `word_ids`, `picture_ids`, `pair_ids`
+#### `POST /api/objects` — Neues Object anlegen
+
+```bash
+curl -X POST "$BASE/api/objects" \
+  -H "Authorization: Bearer $TOKEN" \
+  -H "Content-Type: application/json" \
+  -d '{"notes": "Erste Notiz", "selections": {"key": "value"}}'
+```
+
+#### `PATCH /api/objects/:id` — Felder aktualisieren
+
+```bash
+# Publizieren
+curl -X PATCH "$BASE/api/objects/<ID>" \
+  -H "Authorization: Bearer $TOKEN" \
+  -H "Content-Type: application/json" \
+  -d '{"status": "published"}'
+
+# Blockieren mit Thema
+curl -X PATCH "$BASE/api/objects/<ID>" \
+  -H "Authorization: Bearer $TOKEN" \
+  -H "Content-Type: application/json" \
+  -d '{"status": "blocked", "blocked_topic": "Inhalt ungeeignet"}'
+```
+
+#### `DELETE /api/objects/:id` — Object löschen (entfernt auch alle Verknüpfungen)
+
+#### `POST /api/objects/:id/words/:wordId` — Word verknüpfen
+#### `DELETE /api/objects/:id/words/:wordId` — Word-Verknüpfung lösen
+#### `POST /api/objects/:id/pictures/:pictureId` — Bild verknüpfen
+#### `DELETE /api/objects/:id/pictures/:pictureId` — Bild-Verknüpfung lösen
+#### `POST /api/objects/:id/pairs/:pairId` — Pair verknüpfen
+#### `DELETE /api/objects/:id/pairs/:pairId` — Pair-Verknüpfung lösen
+
+---
+
 ### Utilities
 
 #### `GET /api/tables`