Add Context7 Documentation Source

[butschster]

This PR adds a new docs source type that integrates with Context7 documentation service, allowing users to retrieve targeted documentation content based on library, topic, and token limits.

Features

• New docs source type for accessing Context7 documentation
• Library/topic/token-based filtering for precise content retrieval
• Complete integration with existing modifier and content builder systems
• JSON schema validation for configuration files

Example Usage

sources:
  - type: docs
    library: "laravel/docs"
    topic: controller
    tokens: 600
    description: "Laravel controller documentation"
    tags: ["laravel", "docs"]

---

Features

• New docs-search tool for discovering available documentation libraries
• Configuration options via MCP_DOCS_TOOLS_ENABLED environment variable

Implementation Details

• Added DocsSearchAction to query Context7's search API (https://context7.com/api/v1/search)
• Extended McpConfig with docs tools configuration options
• Updated McpServerBootloader to conditionally register docs tools
• Created documentation showing search and retrieval workflows

Benefits

• Enables AI assistants to find and retrieve relevant documentation on demand
• Complements the docs source type for static context generation
• Provides direct access to specialized documentation without storing it locally
• Supports efficient token usage through customizable token limits

[codecov]

Codecov Report

Attention: Patch coverage is 16.73307% with 209 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
...c/McpServer/Action/Tools/Docs/DocsSearchAction.php	0.00%	86 Missing ⚠️
src/Source/Docs/DocsSourceFetcher.php	2.27%	86 Missing ⚠️
src/Source/Docs/DocsSourceFactory.php	9.52%	19 Missing ⚠️
src/Source/Docs/DocsSource.php	0.00%	10 Missing ⚠️
src/McpServer/McpServerBootloader.php	44.44%	5 Missing ⚠️
src/McpServer/McpConfig.php	0.00%	2 Missing ⚠️
src/Source/Gitlab/GitlabSourceFetcher.php	92.30%	1 Missing ⚠️

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