fix: improve URL path handling in local storage for special characters (#4378)

* refactor: improve URL path handling in local storage system

Enhanced the local storage implementation to properly handle URL-decoded paths
and fix issues with file paths containing special characters. Added decodedPath
field to localStorage struct to separate URL parsing concerns from file system
operations.

Key changes:
- Added decodedPath field to localStorage struct for proper URL decoding
- Modified newLocalStorage to use decoded path instead of modifying original URL
- Fixed Windows path handling to work with decoded paths
- Improved URL escaping in storage.For() to handle special characters
- Added comprehensive test suite covering URL decoding, symlink resolution,
  Windows paths, and edge cases
- Refactored test extractor to use mockTestExtractor for better isolation

This ensures that file paths with spaces, hash symbols, and other special
characters are handled correctly throughout the storage system.

Signed-off-by: Deluan <deluan@navidrome.org>

* fix(tests): fix test file permissions and add missing tests.Init call

* refactor(tests): remove redundant test

Signed-off-by: Deluan <deluan@navidrome.org>

* fix: URL building for Windows and remove redundant variable

Signed-off-by: Deluan <deluan@navidrome.org>

* refactor: simplify URL path escaping in local storage

Signed-off-by: Deluan <deluan@navidrome.org>

---------

Signed-off-by: Deluan <deluan@navidrome.org>

core/storage/storage_test.go

@@ -65,6 +65,21 @@ var _ = Describe("Storage", func() {
 			_, err := For("webdav:///tmp")
 			Expect(err).To(HaveOccurred())
 		})
+		DescribeTable("should handle paths with special characters correctly",
+			func(inputPath string) {
+				s, err := For(inputPath)
+				Expect(err).ToNot(HaveOccurred())
+				Expect(s).To(BeAssignableToTypeOf(&fakeLocalStorage{}))
+				Expect(s.(*fakeLocalStorage).u.Scheme).To(Equal("file"))
+				// The path should be exactly the same as the input - after URL parsing it gets decoded back
+				Expect(s.(*fakeLocalStorage).u.Path).To(Equal(inputPath))
+			},
+			Entry("hash symbols", "/tmp/test#folder/file.mp3"),
+			Entry("spaces", "/tmp/test folder/file with spaces.mp3"),
+			Entry("question marks", "/tmp/test?query/file.mp3"),
+			Entry("ampersands", "/tmp/test&amp/file.mp3"),
+			Entry("multiple special chars", "/tmp/Song #1 & More?.mp3"),
+		)
 	})
 })