v0.2.0: visualizations, interactive browser, arXiv paper, gap analysis

New features:
- 12 interactive visualizations (ietf viz): t-SNE landscape, similarity
  heatmap, score distributions, timeline, bubble explorer, radar charts,
  author network graph, category treemap, quality vs overlap, org bar chart,
  ideas chart, and interactive draft browser
- Interactive draft browser (browser.html): filterable by category, keyword,
  score sliders with sortable table and expandable detail rows
- arXiv paper (paper/main.tex): 13-page manuscript with all findings
- Gap analysis: 12 identified under-addressed areas
- Author network: collaboration graph, org contributions, cross-org analysis
- Draft generation from gaps (ietf draft-gen)
- Auto-load .env for API keys (python-dotenv)

New modules: visualize.py, authors.py, draftgen.py
New reports: timeline, overlap-matrix, authors, gaps
New deps: plotly, matplotlib, seaborn, scipy, scikit-learn, networkx, python-dotenv

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/ietf_analyzer/config.py

@@ -26,6 +26,7 @@ class Config:
     ollama_url: str = "http://localhost:11434"
     ollama_embed_model: str = "nomic-embed-text"
     claude_model: str = "claude-sonnet-4-20250514"
+    claude_model_cheap: str = "claude-haiku-4-5-20251001"
     search_keywords: list[str] = field(default_factory=lambda: list(DEFAULT_KEYWORDS))
     # Only fetch drafts newer than this (ISO date string)
     fetch_since: str = "2024-01-01"