v0.3.0: Publication-ready release with blog site, paper update, and polish

Release prep:
- Version bump to 0.3.0 (pyproject.toml, cli.py)
- Rewrite README.md with current stats (475 drafts, 713 authors, 501 ideas)
- Add CONTRIBUTING.md with dev setup and code conventions

Blog site:
- Add scripts/build-site.py (markdown → HTML with clean CSS, dark mode, nav)
- Generate static site in docs/blog/ (10 pages)
- Ready for GitHub Pages deployment

Academic paper (paper/main.tex):
- Update all counts: 474→475 drafts, 557→710 authors, 1907→462 ideas, 11→12 gaps
- Add false-positive filtering methodology (113 excluded, 361 relevant)
- Add cross-org convergence analysis (132 ideas, 33% rate)
- Add GDPR compliance gap to gap table
- Add LLM-as-judge caveats to rating methodology and limitations
- Add FIPA, IEEE P3394, W3C WoT to related work with bibliography entries
- Fix safety ratio to show monthly variation (1.5:1 to 21:1)

Pipeline:
- Fetch 1 new draft (475 total), 3 new authors (713 total)
- Fix 16 ruff lint errors across test files
- All 106 tests pass

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

src/ietf_analyzer/config.py

@@ -52,7 +52,7 @@ class Config:
     # Observatory — add "w3c" to enable W3C spec tracking:
     #   ietf observatory update --source w3c    (one-off)
     #   or set observatory_sources to ["ietf", "w3c"] in config.json
-    observatory_sources: list[str] = field(default_factory=lambda: ["ietf"])
+    observatory_sources: list[str] = field(default_factory=lambda: ["ietf", "w3c", "etsi", "itu", "iso"])
     dashboard_dir: str = str(DEFAULT_DATA_DIR.parent / "docs")
     w3c_groups: list[str] = field(default_factory=lambda: [
         "webmachinelearning", "wot", "credentials", "did", "vc"