refactor(opencode): native SDK tools, drop MCP, trim skills, expand telemetry

Reworks @mem0/opencode-plugin to expose memory operations as native OpenCode
tools (via the @opencode-ai/plugin `tool()` helper, backed by the mem0ai SDK)
instead of delegating to the remote MCP server. Skills load via the `config`
hook (`skills.paths`) instead of being copied into the project `.opencode/`.

- Drop MCP: remove the regex-based MCP tool interception, the bundled
  opencode.json MCP registration, and the cli.ts installer (mem0-opencode bin).
- Native tools: add_memory, search_memories, get_memories, get_memory,
  update_memory, delete_memory, delete_all_memories, delete_entities,
  list_entities, get_event_status.
- Trim skills 16 -> 8 (context-loader, dream, forget, health, peek, pin,
  remember, tour); remove import, export, memory-reviewer, mem0, list-projects,
  switch-project, stats, onboard. De-MCP/onboard wording in kept skills.
- Telemetry: emit the full shared plugin.* schema (adds user_prompt, bash_error,
  pre_compact, session_stop alongside session_start, tool_use); tool_use now
  fires from inside each native tool; add project_hash + os_version props.
- Fix duplicate error-search (single topK:6); correct the documented
  experimental.chat.messages.transform hook name.
- Bump to 0.2.0.

integrations/mem0-plugin/.opencode-plugin/opencode-skills/health/SKILL.md

@@ -1,6 +1,6 @@
 ---
 name: health
-description: Diagnoses mem0 connectivity, API key validity, and memory read/write functionality. Use when memory operations fail, searches return empty, add_memory errors occur, MCP connection drops, or to verify the plugin is working correctly.
+description: Diagnoses mem0 connectivity, API key validity, and memory read/write functionality. Use when memory operations fail, searches return empty, add_memory errors occur, or to verify the plugin is working correctly.
 ---
 
 # Mem0 Health Check
@@ -37,7 +37,7 @@ echo "branch=$(git branch --show-current 2>/dev/null || echo '')"
 
 PASS if all three are non-empty. WARN if any falls back to defaults.
 
-### Check 3: MCP server connectivity
+### Check 3: Memory tool connectivity
 
 Call `search_memories` with:
 - `query="health check"`
@@ -82,7 +82,7 @@ echo "branch=${MEM0_BRANCH:-}"
 
 PASS  API Key         m0-dVe...
 PASS  Identity        user=kartik, project=mem0, branch=main
-PASS  MCP Connection  142ms
+PASS  Memory Tools    142ms
 PASS  Write/Read      write + delete OK
 PASS  Session         session_id=abc123, app_id=mem0, branch=main