chore(plugin): bump mem0 plugin to v0.1.2

Reflects the changes that landed in #5076:
  - Hook cleanup: session_id capture, key gate, regex tightening,
    opt-in MEM0_DEBUG logging, PreCompact dedup
  - Deterministic mem0 user_id resolver across machines
  - Compaction flow: infer=False on agent's pre-compact summary +
    background capture of platform's compact summary
  - Coding-focused custom-categories setup script
  - expiration_date on session_state and compact_summary captures
  - "Updating the plugin" README section

Bumped in both .claude-plugin/marketplace.json (canonical version
pin) and mem0-plugin/.claude-plugin/plugin.json (cosmetic display).

.claude-plugin/marketplace.json

@@ -12,7 +12,7 @@
       "name": "mem0",
       "source": "./mem0-plugin",
       "description": "Mem0 memory layer for AI applications. Add persistent memory, personalization, and semantic search to Claude workflows.",
-      "version": "0.1.1"
+      "version": "0.1.2"
     }
   ]
 }

mem0-plugin/.claude-plugin/plugin.json

@@ -1,6 +1,6 @@
 {
   "name": "mem0",
-  "version": "0.1.1",
+  "version": "0.1.2",
   "description": "Mem0 memory layer for AI applications. Add persistent memory, personalization, and semantic search to Claude workflows using the Mem0 Platform MCP server.",
   "author": {
     "name": "Mem0",