fix: use moodStarShortcut+moodMap for liked state, warn on silent fail (v0.4.6)

FW_DEBUG=1 investigation revealed:
- wallmood can silently fail (200 OK, frozen modifDate, no state change) due to
  self-like restriction, unsupported post type (FAMILY_CREATED), or rate limit
- Response contains two complementary like indicators: moodStarShortcut (primary)
  and moodMap (secondary) — both must be checked
- liked: false with like=True now surfaces a warning instead of silently
  returning a misleading result
- SPEC.md documents silent-fail scenarios and dual indicator pattern

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

src/mcp_familywall/server.py

@@ -532,14 +532,27 @@ def like_post(post_id: str, like: bool = True) -> str:
             indent=2,
         )
 
-    # Confirm the STAR is present in moodMap (server-side representation of a like).
-    now_liked = any("STAR" in moods for moods in mood_map.values())
+    # Two complementary indicators for the like state:
+    # - moodStarShortcut: direct boolean per-user flag on the post object (primary)
+    # - moodMap: dict of accountId → [mood types]; contains "STAR" when liked (secondary)
+    # Use both so either storage path is covered.
+    star_shortcut = wall_obj.get("moodStarShortcut") == "true"
+    star_in_map = any("STAR" in moods for moods in mood_map.values())
+    now_liked = star_shortcut or star_in_map
 
-    return json.dumps(
-        {"liked": now_liked, "id": post_id, "author": account_id},
-        ensure_ascii=False,
-        indent=2,
-    )
+    result: dict[str, Any] = {"liked": now_liked, "id": post_id, "author": account_id}
+
+    # Surface a warning when the like call apparently had no effect, so the
+    # caller can distinguish a successful like from a silent API rejection
+    # (e.g. rate limit, unsupported post type, or self-like restriction).
+    if not now_liked:
+        result["warning"] = (
+            "Like may not have been applied. "
+            "Possible causes: rate limit, unsupported post type (e.g. FAMILY_CREATED), "
+            "or self-like restriction."
+        )
+
+    return json.dumps(result, ensure_ascii=False, indent=2)
 
 
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