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>

README.md

@@ -2,7 +2,7 @@
 
 MCP server for [Family Wall](https://www.familywall.com) -- read and manage your family's circles, lists, and tasks directly from Claude.
 
-## Features (v0.4.5)
+## Features (v0.4.6)
 
 ### Read