fix(engine): wire notes into post and page rendering (#59)

[x3ek]

Summary

• Fetch notes from NotesService.get_for_path() in post and page routers instead of hardcoding []
• Public notes visible to all users, private notes only to authenticated admins
• Extract shared is_admin helper from posts.py to dependencies.py to avoid duplication
• Update existing tests to mock the new NotesService dependency

Closes #59

Test plan

• python scripts/run-checks.py — 4/4 checks pass (format, lint, 137 tests, pyright)
• Manual: public note renders on post page (default theme)
• Manual: public note renders on static page (default theme)
• Manual: private note visible in admin mode, hidden for non-admin visitors
• Manual: notes render correctly in blue-tech theme
• Manual: notes render correctly in terminal theme

🤖 Generated with Claude Code

[Copilot]

Pull request overview

Wires database-backed notes into post and static page rendering so templates receive the correct notes list, with private notes gated to admins.

Changes:

• Fetch notes via NotesService.get_for_path() in get_post and get_page instead of hardcoding [].
• Add DB session injection to post/page render routes to support notes queries.
• Extract is_admin helper to dependencies.py and update tests to match.

Reviewed changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
src/squishmark/routers/posts.py	Injects DB session and fetches notes for /posts/{slug} during post rendering.
src/squishmark/routers/pages.py	Injects DB session and fetches notes for /{slug} during page rendering.
src/squishmark/dependencies.py	Introduces shared is_admin(request) helper.
tests/test_posts.py	Updates admin-detection tests to import/patch the moved is_admin.
tests/test_notes_rendering.py	Adds coverage asserting notes are fetched and passed to theme rendering for posts/pages.
tests/test_nav_pages.py	Updates router tests to account for new DB/notes dependencies.