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_formula_content.py

@@ -1,42 +1,61 @@
-"""Tests for formula content: correct paths and valid Ruby class name."""
+"""Tests for cask content: correct font paths and valid cask identifier."""
 import re
 
 import pytest
 
-from tests.conftest import FONT_FILES_DIR, FORMULA_DIR, get_font_dir_names
+from tests.conftest import CASKS_DIR, FONT_FILES_DIR, get_font_dir_names
 
 
-def formula_name_to_class(formula_name: str) -> str:
-    """Same logic as generator: formula name to PascalCase (no hyphens)."""
-    parts = re.split(r"[-_]+", formula_name)
-    return "".join(p.capitalize() for p in parts if p)
+def _skip_if_no_cask(font_name):
+    cask_path = CASKS_DIR / f"{font_name}.rb"
+    if not cask_path.exists():
+        pytest.skip(f"No cask for {font_name} (no installable font files)")
 
 
 @pytest.mark.parametrize("font_name", get_font_dir_names())
-def test_formula_references_correct_font_path(font_name):
-    """Generated formula contains the correct font_files/font-<name>/ path."""
-    formula_path = FORMULA_DIR / f"{font_name}.rb"
-    content = formula_path.read_text()
-    # Install block should reference this font path
+def test_cask_references_correct_font_path(font_name):
+    """Generated cask contains the correct font_files/font-<name>/ path."""
+    _skip_if_no_cask(font_name)
+    cask_path = CASKS_DIR / f"{font_name}.rb"
+    content = cask_path.read_text()
     assert f"font_files/{font_name}/" in content, (
-        f"{font_name}: formula does not reference font_files/{font_name}/"
+        f"{font_name}: cask does not reference font_files/{font_name}/"
     )
 
 
 @pytest.mark.parametrize("font_name", get_font_dir_names())
-def test_formula_class_name_valid_and_matches(font_name):
-    """Formula defines class Font<PascalCase> with no hyphens (valid Ruby)."""
-    formula_path = FORMULA_DIR / f"{font_name}.rb"
-    content = formula_path.read_text()
-    formula_name = font_name.replace("font-", "", 1)
-    expected_class = "Font" + formula_name_to_class(formula_name)
-    # Class line: class FontSomething < Formula
-    match = re.search(r"class\s+(Font\w+)\s+<\s+Formula", content)
-    assert match, f"{font_name}: no 'class Font... < Formula' found"
-    actual_class = match.group(1)
-    assert "-" not in actual_class, (
-        f"{font_name}: Ruby class name must not contain hyphens (got {actual_class})"
-    )
-    assert actual_class == expected_class, (
-        f"{font_name}: expected class {expected_class}, got {actual_class}"
+def test_cask_identifier_matches(font_name):
+    """Cask declares the correct identifier matching the file name."""
+    _skip_if_no_cask(font_name)
+    cask_path = CASKS_DIR / f"{font_name}.rb"
+    content = cask_path.read_text()
+    match = re.search(r'cask\s+"([^"]+)"\s+do', content)
+    assert match, f"{font_name}: no 'cask \"...\" do' found"
+    assert match.group(1) == font_name, (
+        f"{font_name}: expected cask \"{font_name}\", got \"{match.group(1)}\""
     )
+
+
+@pytest.mark.parametrize("font_name", get_font_dir_names())
+def test_cask_has_font_artifacts(font_name):
+    """Cask declares at least one font artifact."""
+    _skip_if_no_cask(font_name)
+    cask_path = CASKS_DIR / f"{font_name}.rb"
+    content = cask_path.read_text()
+    font_lines = re.findall(r'^\s*font\s+"[^"]+"', content, re.MULTILINE)
+    assert font_lines, f"{font_name}: cask has no font artifacts"
+
+
+@pytest.mark.parametrize("font_name", get_font_dir_names())
+def test_cask_font_files_exist_on_disk(font_name):
+    """Every font artifact declared in the cask corresponds to a real file in font_files/."""
+    _skip_if_no_cask(font_name)
+    cask_path = CASKS_DIR / f"{font_name}.rb"
+    content = cask_path.read_text()
+    # Extract paths from font "..." lines
+    paths = re.findall(r'^\s*font\s+"([^"]+)"', content, re.MULTILINE)
+    for rel_path in paths:
+        full_path = FONT_FILES_DIR.parent / rel_path
+        assert full_path.is_file(), (
+            f"{font_name}: font artifact references missing file: {rel_path}"
+        )