fix: support Home Manager declarations format in parser

The options.json parser expected declarations as []string (NixOS format),
but Home Manager uses [{name, url}] objects. This caused most HM options
to be silently skipped during parsing (27 vs 4880 options).

Changes:
- Parse declarations as json.RawMessage and try both formats
- Handle HM path format <home-manager/modules/...> in normalizeDeclarationPath
- Add /modules/ marker for HM store paths

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

internal/nixos/parser.go

@@ -40,7 +40,7 @@ type ParsedOption struct {
 
 // optionJSON is the internal structure for parsing options.json entries.
 type optionJSON struct {
-	Declarations []string        `json:"declarations"`
+	Declarations json.RawMessage `json:"declarations"` // Can be []string or []{name, url}
 	Default      json.RawMessage `json:"default,omitempty"`
 	Description  interface{}     `json:"description"` // Can be string or object
 	Example      json.RawMessage `json:"example,omitempty"`
@@ -58,11 +58,8 @@ func parseOption(name string, data json.RawMessage) (*ParsedOption, error) {
 	// Handle description which can be a string or an object with _type: "mdDoc"
 	description := extractDescription(opt.Description)
 
-	// Convert declarations to relative paths
-	declarations := make([]string, 0, len(opt.Declarations))
-	for _, d := range opt.Declarations {
-		declarations = append(declarations, normalizeDeclarationPath(d))
-	}
+	// Parse declarations - can be []string (NixOS) or []{name, url} (Home Manager)
+	declarations := parseDeclarations(opt.Declarations)
 
 	return &ParsedOption{
 		Name:         name,
@@ -75,6 +72,39 @@ func parseOption(name string, data json.RawMessage) (*ParsedOption, error) {
 	}, nil
 }
 
+// parseDeclarations handles both NixOS format ([]string) and Home Manager format ([]{name, url}).
+func parseDeclarations(raw json.RawMessage) []string {
+	if len(raw) == 0 {
+		return nil
+	}
+
+	// Try []string first (NixOS format)
+	var stringDecls []string
+	if err := json.Unmarshal(raw, &stringDecls); err == nil {
+		result := make([]string, 0, len(stringDecls))
+		for _, d := range stringDecls {
+			result = append(result, normalizeDeclarationPath(d))
+		}
+		return result
+	}
+
+	// Try []{name, url} format (Home Manager format)
+	var objectDecls []struct {
+		Name string `json:"name"`
+		URL  string `json:"url"`
+	}
+	if err := json.Unmarshal(raw, &objectDecls); err == nil {
+		result := make([]string, 0, len(objectDecls))
+		for _, d := range objectDecls {
+			// Use name field, normalize the path
+			result = append(result, normalizeDeclarationPath(d.Name))
+		}
+		return result
+	}
+
+	return nil
+}
+
 // extractDescription extracts the description string from various formats.
 func extractDescription(desc interface{}) string {
 	switch v := desc.(type) {
@@ -93,16 +123,29 @@ func extractDescription(desc interface{}) string {
 	return ""
 }
 
-// normalizeDeclarationPath converts a full store path to a relative nixpkgs path.
-// Input: "/nix/store/xxx-source/nixos/modules/services/web-servers/nginx/default.nix"
-// Output: "nixos/modules/services/web-servers/nginx/default.nix"
+// normalizeDeclarationPath converts a full store path to a relative path.
+// NixOS input: "/nix/store/xxx-source/nixos/modules/services/web-servers/nginx/default.nix"
+// NixOS output: "nixos/modules/services/web-servers/nginx/default.nix"
+// HM input: "<home-manager/modules/programs/git.nix>"
+// HM output: "modules/programs/git.nix"
 func normalizeDeclarationPath(path string) string {
-	// Look for common prefixes and strip them
+	// Handle Home Manager format: <home-manager/path> or <nixpkgs/path>
+	if len(path) > 2 && path[0] == '<' && path[len(path)-1] == '>' {
+		inner := path[1 : len(path)-1]
+		// Strip the prefix (home-manager/, nixpkgs/, etc.)
+		if idx := findSubstring(inner, "/"); idx >= 0 {
+			return inner[idx+1:]
+		}
+		return inner
+	}
+
+	// Look for common prefixes and strip them (NixOS store paths)
 	markers := []string{
 		"/nixos/",
 		"/pkgs/",
 		"/lib/",
 		"/maintainers/",
+		"/modules/", // For home-manager paths
 	}
 
 	for _, marker := range markers {