Convert from Homebrew Formulae to Casks for font installation

Formulae can't install to ~/Library/Fonts/ due to Homebrew sandboxing.
Casks have a built-in `font` artifact that handles this automatically.

- Replace Formula/ with Casks/ directory
- Rewrite generator to produce cask files instead of formulae
- Add .ttc (TrueType Collection) support
- Update all tests for cask format
- Update CLI and documentation
- Fonts with no installable files (TTF/OTF/TTC) are skipped

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

tests/test_no_orphan_formulae.py

@@ -1,34 +1,40 @@
-"""Global tests: no orphan formulae, no duplicate formula names."""
-import pytest
-
-from tests.conftest import FONT_FILES_DIR, FORMULA_DIR, get_font_dir_names
+"""Global tests: no orphan casks, no duplicate cask names."""
+from tests.conftest import CASKS_DIR, FONT_FILES_DIR, get_font_dir_names
 
 
-def test_every_formula_has_matching_font_folder():
-    """Every Formula/font-*.rb has a matching font_files/font-<name>/ directory."""
-    formula_files = sorted(FORMULA_DIR.glob("font-*.rb"))
-    for formula_path in formula_files:
-        name = formula_path.stem  # e.g. font-acrylic-hand
+def test_every_cask_has_matching_font_folder():
+    """Every Casks/font-*.rb has a matching font_files/font-<name>/ directory."""
+    cask_files = sorted(CASKS_DIR.glob("font-*.rb"))
+    for cask_path in cask_files:
+        name = cask_path.stem  # e.g. font-acrylic-hand
         font_dir = FONT_FILES_DIR / name
         assert font_dir.is_dir(), (
-            f"Orphan formula: {formula_path.name} has no matching font folder {font_dir}"
+            f"Orphan cask: {cask_path.name} has no matching font folder {font_dir}"
         )
 
 
-def test_no_duplicate_formula_names():
-    """Only one formula file per font-<name> (no duplicate basenames)."""
-    formula_files = list(FORMULA_DIR.glob("font-*.rb"))
-    names = [p.stem for p in formula_files]
+def test_no_duplicate_cask_names():
+    """Only one cask file per font-<name> (no duplicate basenames)."""
+    cask_files = list(CASKS_DIR.glob("font-*.rb"))
+    names = [p.stem for p in cask_files]
     seen = set()
     for n in names:
-        assert n not in seen, f"Duplicate formula name: {n}.rb"
+        assert n not in seen, f"Duplicate cask name: {n}.rb"
         seen.add(n)
 
 
-def test_formula_count_matches_font_count():
-    """Number of font-*.rb formulae equals number of font-* directories."""
+def test_cask_count_matches_font_count():
+    """Number of font-*.rb casks equals number of font-* directories with TTF/OTF files."""
     font_names = get_font_dir_names()
-    formula_count = len(list(FORMULA_DIR.glob("font-*.rb")))
-    assert formula_count == len(font_names), (
-        f"Formula count ({formula_count}) != font dir count ({len(font_names)})"
+    # Only count fonts that have TTF or OTF files (casks skip fonts with no installable files)
+    fonts_with_files = []
+    for name in font_names:
+        font_dir = FONT_FILES_DIR / name
+        has_ttf = any((font_dir / "ttf").glob("*.ttf")) or any((font_dir / "ttf").glob("*.ttc"))
+        has_otf = any((font_dir / "otf").glob("*.otf"))
+        if has_ttf or has_otf:
+            fonts_with_files.append(name)
+    cask_count = len(list(CASKS_DIR.glob("font-*.rb")))
+    assert cask_count == len(fonts_with_files), (
+        f"Cask count ({cask_count}) != font dir count with TTF/OTF ({len(fonts_with_files)})"
     )