Add OAuth2/OpenID Connect authorization server

Implement a full OAuth2 2.0 and OpenID Connect 1.0 authorization
server with support for authorization code flow (with PKCE),
refresh token rotation, device authorization grant, dynamic
client registration, token introspection, and token revocation.

Includes database schema, coredata layer, service logic, HTTP
handlers, OIDC discovery endpoint, and JWKS publishing.

Signed-off-by: Bryan Frimin <bryan@getprobo.com>

pkg/cli/config/config.go

@@ -27,7 +27,13 @@ import (
 	"gopkg.in/yaml.v3"
 )
 
-const DefaultHTTPTimeout = 30 * time.Second
+const (
+	DefaultHTTPTimeout = 30 * time.Second
+
+	// CLIClientID is the well-known OAuth2 client ID for the Probo CLI,
+	// pre-provisioned in every Probo database via migration.
+	CLIClientID = "AAAAAAAAAAAASwAAAAAAAAAAcHJiY2xp"
+)
 
 type (
 	Config struct {
@@ -41,8 +47,10 @@ type (
 	}
 
 	HostConfig struct {
-		Token        string `yaml:"token"`
-		Organization string `yaml:"organization"`
+		Token         string `yaml:"token"`
+		RefreshToken  string `yaml:"refresh_token,omitempty"`
+		TokenEndpoint string `yaml:"token_endpoint,omitempty"`
+		Organization  string `yaml:"organization"`
 	}
 )