feat: add audiobook-mcp validation and fix Dockerfile

Build and validate audiobook-mcp server for audiobook management.

Changes:
- dockerfiles/audiobook-mcp/Dockerfile: Fixed esbuild ETXTBSY error
  by using 'npm install --ignore-scripts' instead of 'npm ci'
- STATUS.md: Added audiobook-mcp as validated MCP (v1.1.0, 361MB)
- AGENTS.md: Added audiobook-mcp to Productivity & Automation section

Validation:
- Container builds successfully from source
- MCP protocol handshake verified with initialize request
- Protocol version 2024-11-05 confirmed
- Server name: audiobook-library, version 1.1.0
- Requires AUDIOBOOK_ROOT environment variable

dockerfiles/audiobook-mcp/Dockerfile

@@ -6,7 +6,8 @@ WORKDIR /app
 
 COPY package.json package-lock.json* ./
 
-RUN npm ci
+# Use npm install instead of npm ci to avoid esbuild ETXTBSY errors
+RUN npm install --ignore-scripts
 
 COPY . .