refactor(reader): remove vendored pdfjs files from git, drop CJK cmaps

Remove 185 binary files (169 CMaps + 16 standard fonts) from git
tracking. These are build artifacts copied from
node_modules/@bookhoard/foliate-js at build time and should not be
version-controlled.

Changes:
- Remove web/static/vendor/pdfjs/ from git (169 cmap files + 16
  standard font files)
- Add web/static/vendor/ to .gitignore
- Drop CJK cmap copying from build scripts — the app is English-only
  and CJK support can be re-added later if needed (saves ~1.7MB in
  the container image)
- Update all three build scripts (build:ts, build:ts:dev,
  build:ts:watch) to copy only standard_fonts/ from node_modules
- Remove cMapUrl from reader.ts PDF config since we no longer ship
  cmaps
- Keep standardFontDataUrl pointing to the build-copied fonts which
  are needed for PDFs with non-embedded standard fonts (Helvetica,
  Times, Courier, etc.)

.gitignore

@@ -68,6 +68,9 @@ Thumbs.db
 # Uploads
 uploads/
 
+# Vendored build artifacts (copied from node_modules at build time)
+web/static/vendor/
+
 # Database
 *.db
 *.sqlite