[v15.0/forgejo] fix(api): package name in route not properly unescaped (#11829)

**Backport:** https://codeberg.org/forgejo/forgejo/pulls/11822

This pull fixes the issue described in https://codeberg.org/forgejo/forgejo/issues/11427 .

The api handler of link/unlink packages use escaped path params to find packages. It causes errors when it comes to npm packages, which contains characters like `@` and `/`.

## Checklist

The [contributor guide](https://forgejo.org/docs/next/contributor/) contains information that will be helpful to first time contributors. All work and communication must conform to Forgejo's [AI Agreement](https://codeberg.org/forgejo/governance/src/branch/main/AIAgreement.md). There also are a few [conditions for merging Pull Requests in Forgejo repositories](https://codeberg.org/forgejo/governance/src/branch/main/PullRequestsAgreement.md). You are also welcome to join the [Forgejo development chatroom](https://matrix.to/#/#forgejo-development:matrix.org).

### Tests for Go changes

(can be removed for JavaScript changes)

- I added test coverage for Go changes...
  - [ ] in their respective `*_test.go` for unit tests.
  - [x] in the `tests/integration` directory if it involves interactions with a live Forgejo server.
- I ran...
  - [x] `make pr-go` before pushing

### Tests for JavaScript changes

(can be removed for Go changes)

- I added test coverage for JavaScript changes...
  - [ ] in `web_src/js/*.test.js` if it can be unit tested.
  - [ ] in `tests/e2e/*.test.e2e.js` if it requires interactions with a live Forgejo server (see also the [developer guide for JavaScript testing](https://codeberg.org/forgejo/forgejo/src/branch/forgejo/tests/e2e/README.md#end-to-end-tests)).

### Documentation

- [ ] I created a pull request [to the documentation](https://codeberg.org/forgejo/docs) to explain to Forgejo users how to use this change.
- [x] I did not document these changes and I do not expect someone else to do it.

### Release notes

- [x] This change will be noticed by a Forgejo user or admin (feature, bug fix, performance, etc.). I suggest to include a release note for this change.
- [ ] This change is not visible to a Forgejo user or admin (refactor, dependency upgrade, etc.). I think there is no need to add a release note for this change.

*The decision if the pull request will be shown in the release notes is up to the mergers / release team.*

The content of the `release-notes/<pull request number>.md` file will serve as the basis for the release notes. If the file does not exist, the title of the pull request will be used instead.

Co-authored-by: Guangxiong Lin <hi@gxlin.org>
Reviewed-on: https://codeberg.org/forgejo/forgejo/pulls/11829
Reviewed-by: Mathieu Fenniak <mfenniak@noreply.codeberg.org>
Co-authored-by: forgejo-backport-action <forgejo-backport-action@noreply.codeberg.org>
Co-committed-by: forgejo-backport-action <forgejo-backport-action@noreply.codeberg.org>

tests/integration/api_packages_npm_test.go

@@ -14,6 +14,7 @@ import (
 	auth_model "forgejo.org/models/auth"
 	"forgejo.org/models/db"
 	"forgejo.org/models/packages"
+	unit_model "forgejo.org/models/unit"
 	"forgejo.org/models/unittest"
 	user_model "forgejo.org/models/user"
 	"forgejo.org/modules/packages/npm"
@@ -28,6 +29,8 @@ func TestPackageNpm(t *testing.T) {
 	defer tests.PrepareTestEnv(t)()
 
 	user := unittest.AssertExistsAndLoadBean(t, &user_model.User{ID: 2})
+	session := loginUser(t, user.Name)
+	tokenWritePackage := getTokenForLoggedInUser(t, session, auth_model.AccessTokenScopeWritePackage)
 
 	token := fmt.Sprintf("Bearer %s", getTokenForLoggedInUser(t, loginUser(t, user.Name), auth_model.AccessTokenScopeWritePackage))
 
@@ -117,6 +120,22 @@ func TestPackageNpm(t *testing.T) {
 		assert.Equal(t, int64(192), pb.Size)
 	})
 
+	t.Run("RepositoryLink", func(t *testing.T) {
+		defer tests.PrintCurrentTest(t)()
+
+		// create a repository
+		repo, _, f := tests.CreateDeclarativeRepo(t, user, "", []unit_model.Type{unit_model.TypeCode}, nil, nil)
+		defer f()
+
+		// link to public repository
+		req := NewRequest(t, "POST", fmt.Sprintf("/api/v1/packages/%s/npm/%s/-/link/%s", user.Name, url.QueryEscape(packageName), repo.Name)).AddTokenAuth(tokenWritePackage)
+		MakeRequest(t, req, http.StatusCreated)
+
+		// remove link
+		req = NewRequest(t, "POST", fmt.Sprintf("/api/v1/packages/%s/npm/%s/-/unlink", user.Name, url.QueryEscape(packageName))).AddTokenAuth(tokenWritePackage)
+		MakeRequest(t, req, http.StatusNoContent)
+	})
+
 	t.Run("UploadExists", func(t *testing.T) {
 		defer tests.PrintCurrentTest(t)()