When ListContents is called with a path that points to a file (not a
directory), Gitea returns a single JSON object instead of an array.
Previously this caused json.Unmarshal to fail with:
  json: cannot unmarshal object into Go value of type []gitea.ContentEntry

Now ListContents tries array unmarshal first, and falls back to single
object unmarshal, wrapping it in a slice. This allows patterns-files
config to specify individual files like 'README.md' without triggering
a parse error.

Also updates TestGetAllFilesInPath_File to reflect actual Gitea behavior
(single object response, not 404).

Fixes #73

@@ -454,1 +456,3 @@
-		return nil, fmt.Errorf("parse contents JSON: %w", err)
+		// Gitea returns a single object (not an array) when path is a file
+		var single ContentEntry
+		if err2 := json.Unmarshal(body, &single); err2 != nil {

@@ -453,2 +455,3 @@
 	if err := json.Unmarshal(body, &entries); err != nil {
-		return nil, fmt.Errorf("parse contents JSON: %w", err)
+		// Gitea returns a single object (not an array) when path is a file
+		var single ContentEntry

@@ -452,3 +454,3 @@
 	var entries []ContentEntry
 	if err := json.Unmarshal(body, &entries); err != nil {
-		return nil, fmt.Errorf("parse contents JSON: %w", err)
+		// Gitea returns a single object (not an array) when path is a file

@@ -455,0 +457,4 @@
+		var single ContentEntry
+		if err2 := json.Unmarshal(body, &single); err2 != nil {
+			return nil, fmt.Errorf("parse contents JSON: %w", err)
+		}