config: add OIDC/session env vars for the login gate

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

backend/internal/config/config.go

@@ -9,6 +9,7 @@ import (
 	"fmt"
 	"os"
 	"strconv"
+	"strings"
 	"time"
 )
 
@@ -29,6 +30,21 @@ type Config struct {
 
 	MinConfidence        float64
 	IncrementalSyncEvery time.Duration
+
+	// OIDC login gate (Keycloak). PublicBaseURL is this app's own externally
+	// reachable origin (e.g. "https://geniusrun.example.com") -- it derives
+	// OIDCRedirectURL and whether session cookies can be marked Secure,
+	// instead of requiring both to be configured separately and risking them
+	// drifting out of sync.
+	PublicBaseURL    string
+	OIDCIssuerURL    string
+	OIDCClientID     string
+	OIDCClientSecret string
+	OIDCRedirectURL  string
+	OIDCRequiredRole string
+	SessionSecret    []byte
+	SessionDuration  time.Duration
+	SessionSecure    bool
 }
 
 // Load reads configuration from environment variables, applying defaults
@@ -42,6 +58,12 @@ func Load() (Config, error) {
 		GarminTokenStore:     os.Getenv("GARMIN_TOKENSTORE"),
 		MinConfidence:        getEnvFloat("GENIUSRUN_MIN_CONFIDENCE", 0.6),
 		IncrementalSyncEvery: getEnvDuration("GENIUSRUN_INCREMENTAL_SYNC_EVERY", 6*time.Hour),
+		PublicBaseURL:        strings.TrimRight(os.Getenv("GENIUSRUN_PUBLIC_BASE_URL"), "/"),
+		OIDCIssuerURL:        os.Getenv("GENIUSRUN_OIDC_ISSUER_URL"),
+		OIDCClientID:         os.Getenv("GENIUSRUN_OIDC_CLIENT_ID"),
+		OIDCClientSecret:     os.Getenv("GENIUSRUN_OIDC_CLIENT_SECRET"),
+		OIDCRequiredRole:     getEnvDefault("GENIUSRUN_OIDC_REQUIRED_ROLE", "geniusrun-user"),
+		SessionDuration:      getEnvDuration("GENIUSRUN_SESSION_DURATION", 720*time.Hour),
 	}
 
 	if cfg.GarminPythonPath == "" {
@@ -50,6 +72,26 @@ func Load() (Config, error) {
 	if cfg.GarminServerPath == "" {
 		return cfg, fmt.Errorf("MCP_GARMIN_SERVER is required (path to mcp-garmin's server.py)")
 	}
+	if cfg.PublicBaseURL == "" {
+		return cfg, fmt.Errorf("GENIUSRUN_PUBLIC_BASE_URL is required (e.g. https://geniusrun.example.com)")
+	}
+	if cfg.OIDCIssuerURL == "" {
+		return cfg, fmt.Errorf("GENIUSRUN_OIDC_ISSUER_URL is required")
+	}
+	if cfg.OIDCClientID == "" {
+		return cfg, fmt.Errorf("GENIUSRUN_OIDC_CLIENT_ID is required")
+	}
+	if cfg.OIDCClientSecret == "" {
+		return cfg, fmt.Errorf("GENIUSRUN_OIDC_CLIENT_SECRET is required")
+	}
+	sessionSecret := os.Getenv("GENIUSRUN_SESSION_SECRET")
+	if len(sessionSecret) < 32 {
+		return cfg, fmt.Errorf("GENIUSRUN_SESSION_SECRET is required and must be at least 32 characters")
+	}
+	cfg.SessionSecret = []byte(sessionSecret)
+	cfg.OIDCRedirectURL = cfg.PublicBaseURL + "/api/session/callback"
+	cfg.SessionSecure = strings.HasPrefix(cfg.PublicBaseURL, "https://")
+
 	return cfg, nil
 }