fix: write all theme.json defaults to vault theme frontmatter

Previously, only UI chrome colours and 3 editor vars were written to
theme note frontmatter. CSS vars like --lists-bullet-size, --headings-h1-font-size,
etc. remained unset, so EditorTheme.css rules had no effect.

- Expand DEFAULT_VAULT_THEME_VARS from 46 to 140 entries, covering every
  property from theme.json (editor, headings, lists, checkboxes, inline
  styles, code blocks, blockquote, table, horizontal rule, colors)
- Fix missing px suffix on editor-font-size and editor-max-width
- Add missing semantic vars: bg-card, text-tertiary
- Refactor built-in vault themes from const strings to generated functions
  with per-theme colour overrides (DRY, all themes get editor properties)
- Quote var() references in frontmatter to prevent YAML parse issues
- Add regression tests for create_vault_theme and seed_vault_themes

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

src-tauri/src/theme/create.rs

@@ -93,7 +93,11 @@ fn find_available_stem(dir: &Path, base: &str, ext: &str) -> String {
 fn vault_theme_note_content(name: &str, vars: &[(&str, &str)]) -> String {
     let mut fm = format!("---\nIs A: Theme\nDescription: {name} theme\n");
     for (key, value) in vars {
-        if value.contains('#') || value.contains('\'') || value.contains(',') {
+        if value.contains('#')
+            || value.contains('\'')
+            || value.contains(',')
+            || value.contains('(')
+        {
             fm.push_str(&format!("{key}: \"{value}\"\n"));
         } else {
             fm.push_str(&format!("{key}: {value}\n"));
@@ -216,4 +220,43 @@ mod tests {
         assert_eq!(slugify("default"), "default");
         assert_eq!(slugify("Dark Mode!"), "dark-mode");
     }
+
+    #[test]
+    fn test_create_vault_theme_contains_all_default_css_vars() {
+        let dir = TempDir::new().unwrap();
+        let vault = dir.path().join("vault");
+        fs::create_dir_all(&vault).unwrap();
+        let vp = vault.to_str().unwrap();
+
+        let path = create_vault_theme(vp, Some("Full Theme")).unwrap();
+        let content = fs::read_to_string(&path).unwrap();
+
+        // Every entry in DEFAULT_VAULT_THEME_VARS must appear in the generated file
+        for (key, _) in &DEFAULT_VAULT_THEME_VARS {
+            assert!(
+                content.contains(&format!("{key}:")),
+                "missing key in theme file: {key}"
+            );
+        }
+
+        // Spot-check editor properties from theme.json that were previously missing
+        assert!(content.contains("editor-font-family:"), "missing editor-font-family");
+        assert!(content.contains("editor-padding-horizontal:"), "missing editor-padding-horizontal");
+        assert!(content.contains("headings-h1-font-size:"), "missing headings-h1-font-size");
+        assert!(content.contains("lists-bullet-size:"), "missing lists-bullet-size");
+        assert!(content.contains("lists-bullet-color:"), "missing lists-bullet-color");
+        assert!(content.contains("checkboxes-size:"), "missing checkboxes-size");
+        assert!(content.contains("inline-styles-bold-font-weight:"), "missing inline-styles-bold-font-weight");
+        assert!(content.contains("code-blocks-font-family:"), "missing code-blocks-font-family");
+        assert!(content.contains("blockquote-border-left-width:"), "missing blockquote-border-left-width");
+        assert!(content.contains("table-border-color:"), "missing table-border-color");
+        assert!(content.contains("horizontal-rule-thickness:"), "missing horizontal-rule-thickness");
+        assert!(content.contains("colors-text:"), "missing colors-text");
+        assert!(content.contains("colors-cursor:"), "missing colors-cursor");
+
+        // Numeric values that need CSS units must have px suffix
+        assert!(content.contains("editor-font-size: 15px"), "editor-font-size should have px unit");
+        assert!(content.contains("editor-max-width: 720px"), "editor-max-width should have px unit");
+        assert!(content.contains("editor-padding-horizontal: 40px"), "editor-padding-horizontal should have px unit");
+    }
 }