[WIP] Add web_fetch tool for Rook autonomy

[Copilot]

Thanks for assigning this issue to me. I'm starting to work on it and will keep this PR's description up to date as I form a plan and make progress.

Original prompt

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This section details on the original issue you should resolve

<issue_title>Implement web_fetch tool</issue_title>
<issue_description>Priority: P1 (required for Rook autonomy)

Spec:

• Accept parameters: {url, prompt?}
• Fetch URL content via node:https
• Extract readable text (strip HTML or use @mozilla/readability)
• Optional: pass through LLM for summarization if prompt provided
• Return formatted markdown or plain text

Files:

• Create src/tools/web-fetch.ts
• Register in tool registry
• Add JSON Schema definition

Tests:

• Mock HTTP responses
• HTML extraction validation
• Integration test with agent loop

Acceptance:

• Tool executes via agent loop
• Rook can read documentation, URLs from conversations
• Clean text extraction from common HTML patterns

Ref: gap-analysis-report.md P1-3</issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes Implement web_fetch tool #124

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