Add author detail, idea detail, and gap-draft reverse link pages

- Author detail page (/authors/<person_id>): shows author info, all drafts
  with ratings, and co-authors with shared draft counts. Public route.
- Idea detail page (/ideas/<idea_id>): shows idea metadata, source draft,
  and top-5 most similar ideas via embedding cosine similarity. Admin route.
- Gap detail page: added "Related Drafts" section that finds drafts by
  extracting draft names from evidence text and searching by topic keywords.
- Updated author links across templates to use /authors/<person_id> URLs.
- Added DB methods: get_author_by_id, get_author_drafts, get_coauthors.
- Extended top_authors to include person_id (5th tuple element).

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

src/webui/blueprints/pages.py

@@ -27,6 +27,7 @@ from webui.data import (
     get_ask_search,
     get_citation_influence,
     get_bcp_analysis,
+    get_author_detail,
 )
 
 pages_bp = Blueprint("pages", __name__)
@@ -144,6 +145,14 @@ def architecture():
     return render_template("architecture.html", arch=data)
 
 
+@pages_bp.route("/authors/<int:person_id>")
+def author_detail(person_id: int):
+    detail = get_author_detail(db(), person_id)
+    if not detail:
+        abort(404)
+    return render_template("author_detail.html", author=detail)
+
+
 @pages_bp.route("/authors")
 def authors():
     top = get_top_authors(db(), limit=50)