feat(legal): B-2.9 6 pages légales (CGU, Loi 25, cookies, remboursement, accessibilité, mentions)

- src/legal/__init__.py: define canonical LEGAL_VERSION='2026-04-27' constant
  (single source of truth — auth.py now imports it as SIGNUP_LEGAL_VERSION).
- src/legal/routes.py: add /legal/<page> + /legal/ index routes; markdown rendered
  from src/legal/content/*.md with toc, tables, fenced_code, attr_list extensions.
- src/legal/content/: 6 French (Québec) markdown documents — DictIA Inc. /
  InnovA AI S.E.N.C. branding, Loi 25-compliant 12-section privacy policy,
  WCAG 2.2 AA accessibility statement, AGPL-3.0 attribution. All marked
  DRAFT v1.0 pending legal review by Allison Rioux.
- templates/legal/_layout.html + index.html: extends marketing/base.html;
  inline .legal-content typographic styles (no CSS rebuild required).
- .gitignore: allow-rule for src/legal/content/*.md so markdown is tracked
  despite the global *.md ignore.
- tests/test_legal_pages.py: 9 tests covering 200 responses, DictIA branding,
  rprp@dictia.ca presence, 12 mandatory Loi 25 sections, public indexability
  (no X-Robots-Tag noindex), shared layout, marketing/base.html extension,
  DRAFT callout, and LEGAL_VERSION/SIGNUP_LEGAL_VERSION equivalence.
- tests/_run_legal_pages_windows.py: manual driver (Windows fcntl stub).
- static/css/marketing.css: regenerated by `npm run build:css` to include
  new utility classes referenced from templates/legal/*.html.

Tests: 9/9 pass. No off-limits files modified beyond the 2-line auth.py
constant move spec'd in B-2.9. No schema changes; markdown==3.5.1 already
pinned in requirements.txt (B-1.1). Pages publicly indexable by design
(Loi 25 transparency).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

.gitignore

@@ -27,6 +27,7 @@ changes.txt
 !deployment/**/*.md
 !client_docs/**/*.md
 !client_docs/*.md
+!src/legal/content/*.md
 docker-compose.dev.yml
 docker-compose.lite.yml
 docker-compose.postgres.yml