feat(wall-posts): add wall post reading/writing with comments (v1.3.0)

- Add get_wall_posts: read recent wall posts with like/comment counts
- Add create_wall_post: publish new status posts to the wall
- Add add_comment: add comments to wall posts and activities
- like_post already supports both wall posts and activities (v1.2.0)
- Update README.md with new Wall & Activities section
- Update CLAUDE.md with v1.3.0 and tool reorganization
- Update CHANGELOG.md with v1.3.0 release notes
- Add wallpublish and walladdComment documentation to SPEC.md

Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>

SPEC.md

@@ -304,6 +304,50 @@ a00.r.r                     → Wall-Objekt mit moodMap, refAction: "MOOD_STAR"
 
 **Verifiziert am:** 2026-04-17 via Network-Interceptor (echter Request-Body)
 
+### `wallpublish` – Wall-Post veröffentlichen
+
+POST https://api.familywall.com/api/wallpublish
+
+**Body-Parameter:**
+
+| Parameter | Wert |
+|---|---|
+| `tagline` | Post-Text |
+
+**Response:**
+```
+a00.r.r                     → Wall-Post-Objekt
+  .metaId                   → neue Post-ID
+  .tagline                  → Post-Text
+  .creationDate             → Timestamp (ISO 8601)
+```
+
+**Verifiziert am:** 2026-04-17 via Briefing und Integration
+
+### `walladdComment` – Kommentar hinzufügen
+
+POST https://api.familywall.com/api/walladdComment
+
+**Body-Parameter:**
+
+| Parameter | Wert |
+|---|---|
+| `wall_message_id` | Post-metaId (z.B. `wall/23431854_31119189`) |
+| `comment` | Kommentartext |
+
+**Response:**
+```
+a00.r.r                     → Kommentar-Objekt
+  .metaId                   → neue Kommentar-ID
+  .text                     → Kommentartext
+  .creationDate             → Timestamp (ISO 8601)
+```
+
+**Bekannte Einschränkungen:**
+- `mood` und `clientOpId` sind optional und werden ignoriert
+
+**Verifiziert am:** 2026-04-17 via Briefing und Integration
+
 ### `taskcategoryput` – Kategorie erstellen/aktualisieren
 POST https://api.familywall.com/api/taskcategoryput