feat(auth): store Subsonic API keys hashed; a new key is shown once (M462 #4983)

users.api_token held each user's apiKey in plaintext and was looked up by
equality, so a leaked row or backup handed out working keys. Migration
0063 replaces it with api_token_hash (sha256, hex), computed in place
from the existing keys so every Subsonic client keeps working.

The key can no longer be read back: GET /api/me/api-token is gone, and
POST returns the new key once. Settings shows it right after Regenerate
with a copy button and a "won't be shown again" note.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

internal/api/me_token_test.go

@@ -8,47 +8,23 @@ import (
 	"os"
 	"testing"
 
+	"git.fabledsword.com/bvandeusen/minstrel/internal/auth"
 	"github.com/go-chi/chi/v5"
 )
 
 func newMeTokenRouter(h *handlers) chi.Router {
 	r := chi.NewRouter()
-	r.Get("/api/me/api-token", h.handleGetMyAPIToken)
 	r.Post("/api/me/api-token", h.handleRegenerateMyAPIToken)
 	return r
 }
 
-func TestGetAPIToken_ReturnsCurrentToken(t *testing.T) {
-	if os.Getenv("MINSTREL_TEST_DATABASE_URL") == "" {
-		t.Skip("MINSTREL_TEST_DATABASE_URL not set")
-	}
-	h, pool := testHandlers(t)
-	user := seedUser(t, pool, "tok1", "pw", false)
-
-	req := httptest.NewRequest(http.MethodGet, "/api/me/api-token", nil)
-	req = withUser(req, user)
-	rec := httptest.NewRecorder()
-	newMeTokenRouter(h).ServeHTTP(rec, req)
-
-	if rec.Code != http.StatusOK {
-		t.Fatalf("status = %d, want 200; body=%s", rec.Code, rec.Body.String())
-	}
-	var resp apiTokenResp
-	if err := json.Unmarshal(rec.Body.Bytes(), &resp); err != nil {
-		t.Fatalf("decode: %v", err)
-	}
-	if resp.APIToken != user.ApiToken {
-		t.Errorf("api_token = %q, want %q", resp.APIToken, user.ApiToken)
-	}
-}
-
 func TestRegenerateAPIToken_IssuesNewToken(t *testing.T) {
 	if os.Getenv("MINSTREL_TEST_DATABASE_URL") == "" {
 		t.Skip("MINSTREL_TEST_DATABASE_URL not set")
 	}
 	h, pool := testHandlers(t)
 	user := seedUser(t, pool, "tok2", "pw", false)
-	oldToken := user.ApiToken
+	oldHash := user.ApiTokenHash
 
 	req := httptest.NewRequest(http.MethodPost, "/api/me/api-token", nil)
 	req = withUser(req, user)
@@ -65,20 +41,20 @@ func TestRegenerateAPIToken_IssuesNewToken(t *testing.T) {
 	if resp.APIToken == "" {
 		t.Fatalf("api_token is empty")
 	}
-	if resp.APIToken == oldToken {
-		t.Errorf("api_token unchanged after regenerate")
-	}
-
-	// Verify DB row has the new token and old token no longer matches.
-	var dbToken string
+	// The DB holds the new key's hash, never the key, and the old key no
+	// longer matches.
+	var dbHash string
 	if err := pool.QueryRow(context.Background(),
-		"SELECT api_token FROM users WHERE id = $1", user.ID).Scan(&dbToken); err != nil {
-		t.Fatalf("read token: %v", err)
+		"SELECT api_token_hash FROM users WHERE id = $1", user.ID).Scan(&dbHash); err != nil {
+		t.Fatalf("read token hash: %v", err)
 	}
-	if dbToken != resp.APIToken {
-		t.Errorf("DB api_token = %q, want %q", dbToken, resp.APIToken)
+	if dbHash != auth.HashAPIToken(resp.APIToken) {
+		t.Errorf("DB api_token_hash = %q, want hash of the returned key", dbHash)
 	}
-	if dbToken == oldToken {
-		t.Errorf("old token still in DB after regenerate")
+	if dbHash == oldHash {
+		t.Errorf("old key hash still in DB after regenerate")
+	}
+	if dbHash == resp.APIToken {
+		t.Errorf("DB holds the raw key")
 	}
 }