feat: Add creds for GitHub auth, add "none" auth to publisher (#276)

## Motivation and Context

- Adds credentials for the new MCP Registry Login GitHub Apps (local,
staging, prod)
- Adds support for "none" auth to publisher

## How Has This Been Tested?

- Tested publisher workflows locally
- Unit and integration tests passing

## Breaking Changes

None

## Types of changes
<!-- What types of changes does your code introduce? Put an `x` in all
the boxes that apply: -->
- [ ] Bug fix (non-breaking change which fixes an issue)
- [x] New feature (non-breaking change which adds functionality)
- [ ] Breaking change (fix or feature that would cause existing
functionality to change)
- [ ] Documentation update

## Checklist
<!-- Go over all the following points, and put an `x` in all the boxes
that apply. -->
- [x] I have read the [MCP
Documentation](https://modelcontextprotocol.io)
- [x] My code follows the repository's style guidelines
- [x] New and existing tests pass locally
- [x] I have added appropriate error handling
- [x] I have added or updated documentation as needed

---

Merging based on Tadas's approval review, and only making minor docs changes on top of that.

internal/api/handlers/v0/auth/github.go

@@ -79,7 +79,7 @@ func (h *GitHubHandler) ExchangeToken(ctx context.Context, githubToken string) (
 	}
 
 	// Get user's organizations
-	orgs, err := h.getGitHubUserOrgs(ctx, githubToken)
+	orgs, err := h.getGitHubUserOrgs(ctx, user.Login, githubToken)
 	if err != nil {
 		return nil, fmt.Errorf("failed to get GitHub organizations: %w", err)
 	}
@@ -138,9 +138,8 @@ func (h *GitHubHandler) getGitHubUser(ctx context.Context, token string) (*GitHu
 	return &user, nil
 }
 
-// getGitHubUserOrgs gets the authenticated user's organizations
-func (h *GitHubHandler) getGitHubUserOrgs(ctx context.Context, token string) ([]GitHubUserOrOrg, error) {
-	req, err := http.NewRequestWithContext(ctx, http.MethodGet, h.baseURL+"/user/orgs", nil)
+func (h *GitHubHandler) getGitHubUserOrgs(ctx context.Context, username string, token string) ([]GitHubUserOrOrg, error) {
+	req, err := http.NewRequestWithContext(ctx, http.MethodGet, h.baseURL+"/users/"+username+"/orgs", nil)
 	if err != nil {
 		return nil, fmt.Errorf("failed to create request: %w", err)
 	}

internal/api/handlers/v0/auth/github_test.go

@@ -23,7 +23,7 @@ import (
 
 const (
 	githubUserEndpoint = "/user"
-	githubOrgsEndpoint = "/user/orgs"
+	githubOrgsEndpoint = "/users/testuser/orgs"
 )
 
 func TestGitHubHandler_ExchangeToken(t *testing.T) {
@@ -226,7 +226,7 @@ func TestGitHubHandler_ExchangeToken(t *testing.T) {
 				}
 				w.Header().Set("Content-Type", "application/json")
 				json.NewEncoder(w).Encode(user) //nolint:errcheck
-			case githubOrgsEndpoint:
+			case "/users/user with spaces/orgs":
 				orgs := []v0auth.GitHubUserOrOrg{}
 				w.Header().Set("Content-Type", "application/json")
 				json.NewEncoder(w).Encode(orgs) //nolint:errcheck
@@ -259,7 +259,7 @@ func TestGitHubHandler_ExchangeToken(t *testing.T) {
 			switch r.URL.Path {
 			case githubUserEndpoint:
 				user := v0auth.GitHubUserOrOrg{
-					Login: "validuser",
+					Login: "testuser",
 					ID:    12345,
 				}
 				w.Header().Set("Content-Type", "application/json")
@@ -290,7 +290,7 @@ func TestGitHubHandler_ExchangeToken(t *testing.T) {
 		jwtManager := auth.NewJWTManager(cfg)
 		claims, err := jwtManager.ValidateToken(ctx, response.RegistryToken)
 		require.NoError(t, err)
-		assert.Equal(t, "validuser", claims.AuthMethodSubject)
+		assert.Equal(t, "testuser", claims.AuthMethodSubject)
 		assert.Empty(t, claims.Permissions) // No permissions because one org has invalid name
 	})
 
@@ -538,7 +538,7 @@ func TestValidGitHubNames(t *testing.T) {
 					}
 					w.Header().Set("Content-Type", "application/json")
 					json.NewEncoder(w).Encode(user) //nolint:errcheck
-				case githubOrgsEndpoint:
+				case "/users/" + tc.username + "/orgs":
 					w.Header().Set("Content-Type", "application/json")
 					json.NewEncoder(w).Encode(tc.orgs) //nolint:errcheck
 				}
@@ -596,7 +596,7 @@ func TestConcurrentTokenExchange(t *testing.T) {
 			}
 			w.Header().Set("Content-Type", "application/json")
 			json.NewEncoder(w).Encode(user) //nolint:errcheck
-		case "/user/orgs":
+		case githubOrgsEndpoint:
 			orgs := []v0auth.GitHubUserOrOrg{}
 			w.Header().Set("Content-Type", "application/json")
 			json.NewEncoder(w).Encode(orgs) //nolint:errcheck

internal/config/config.go

@@ -12,6 +12,7 @@ const (
 )
 
 // Config holds the application configuration
+// See .env.example for more documentation
 type Config struct {
 	ServerAddress       string       `env:"SERVER_ADDRESS" envDefault:":8080"`
 	DatabaseType        DatabaseType `env:"DATABASE_TYPE" envDefault:"mongodb"`