Add Claude Code plugin scaffold for single-repo install

Consolidates plugin components (hooks, commands, skills, MCP config)
into this repo so it can be installed with:
  claude plugins install github:ViktorBarzin/claude-memory-mcp

- .claude-plugin/plugin.json: manifest with all hook events
- mcp/memory-mcp.json: MCP server config using existing src/
- hooks/: compaction survival, auto-recall, auto-learn, auto-approve
- commands/: /remember and /recall slash commands
- skills/: memory-management skill
- Bump MCP server to v2.0.0 with metaclaw migration fallback
- Update README with quick install and plugin hooks docs

commands/recall.md

@@ -0,0 +1,10 @@
+---
+allowed-tools: mcp__claude_memory__memory_recall, mcp__plugin_claude-memory_claude_memory__memory_recall
+argument-hint: <query>
+description: Search persistent memory
+---
+
+Search persistent memory for information matching $ARGUMENTS.
+
+Use memory_recall with the query as context and generate an expanded_query with related search terms.
+Present results clearly with when they were stored.

commands/remember.md

@@ -0,0 +1,11 @@
+---
+allowed-tools: mcp__claude_memory__memory_store, mcp__plugin_claude-memory_claude_memory__memory_store
+argument-hint: <fact to remember>
+description: Store a fact in persistent memory
+---
+
+Store the provided fact in persistent memory using the memory_store MCP tool.
+
+Use $ARGUMENTS as the content to store.
+Infer an appropriate category (facts, preferences, projects, people, decisions).
+Confirm what was stored.