Feat/dom source extraction

[joaocarlos]

This PR adds DOM-based source extraction for ask_question, so citations are captured from NotebookLM’s response UI instead of asking the model to generate
them explicitly.

What changed

• Added include_sources?: boolean to ask_question.
• Added global default setting always-include-sources (default true).
• Added config support:
  • CLI: config set always-include-sources <true|false>
  • Env: `NOTEBOOKLM_ALWAYS_INCLUDE_SOURCES=true|false
• Updated `ask_question response payload to include:
  • include_sources (effective value used)
  • `sources (structured parsed references)
• Implemented DOM citation parsing in `page-utils:
  • Extracts from citation elements like `.citation-marker and citation dialog-related buttons.
  • Normalizes citation text into `SourceReference entries.
  • Filters UI noise entries such as ... and “Show additional citations”.

Why implement this?

• Extract directly from the DOM response to reduce model pressure/tokens for citation formatting.
• Uses NotebookLM’s own citation UI as the source of truth.
• Makes source inclusion automatic and configurable globally/per-call.

Validation performed

• `npm run build (pass)
• Live NotebookLM E2E with local build:
  • `includeSources=true returned non-zero source extraction (9 sources in test run).
• MCP stdio integration (tools/call → `ask_question):
  • confirmed include_sources: true
  • confirmed `sources_count > 0

Implementation note

Since I'm not working on a project right now, I could only demonstrate it with an MVP. Further tests should be performed to ensure it does not compromise other features.

Example output

  {
    "success": true,
    "data": {
      "include_sources": true,
      "sources": [
        {
          "title": "J.Puthiyidam and Joseph - 2023 - Prioritization of MQTT Messages A Novel Approach.pdf",
          "raw_text": "1: J.Puthiyidam and Joseph - 2023 - Prioritization of MQTT Messages A Novel Approach.pdf"
        },
        {
          "title": "Shahri et al. - 2022 - Extending MQTT with Real-Time Communication Services Based on SDN.pdf",
          "raw_text": "4: Shahri et al. - 2022 - Extending MQTT with Real-Time Communication Services Based on SDN.pdf"
        }
      ]
    }
  }

Branch: feat/dom-source-extraction
Commit: b898219

Issue

References #20