refactor(log): split location into package/file/class/method, auto-derived

Per the log schema: 'package' is the Go package (absent on
Python-emitted lines), 'file' the Go/Python source basename, 'class' the
Go receiver or Python class (omitted when there is none -- free
functions no longer masquerade under a package-as-class), 'method' the
emitting function. applog.App() now takes no arguments and derives all
of it from runtime.Caller, so labels can never drift from the code; the
manual http/wrapper emitters and forwarded wrapper.py lines (file=
wrapper.py, no package) carry the same fields.

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

backend/internal/api/api_test.go

@@ -1158,8 +1158,8 @@ func TestRequestLoggingMiddleware_LogsMethodPathStatusDuration(t *testing.T) {
 	if err := json.Unmarshal(buf.Bytes(), &entry); err != nil {
 		t.Fatalf("log output is not valid JSON: %v (%q)", err, buf.String())
 	}
-	if entry["type"] != "http" || entry["class"] != "api" || entry["method"] != "loggingMiddleware" {
-		t.Errorf("schema fields = %v, want type=http class=api method=loggingMiddleware", entry)
+	if entry["type"] != "http" || entry["package"] != "api" || entry["file"] != "server.go" || entry["method"] != "loggingMiddleware" {
+		t.Errorf("schema fields = %v, want type=http package=api file=server.go method=loggingMiddleware", entry)
 	}
 	if _, hasMsg := entry["msg"]; hasMsg {
 		t.Errorf("expected no msg on the http record, got %v", entry["msg"])

backend/internal/api/garmin.go

@@ -45,7 +45,7 @@ func (s *Server) recordAuthResult(ctx context.Context, userID int64, res garmin.
 
 	if res.Status == garmin.AuthSuccess {
 		if err := s.DB.MarkGarminConnected(ctx, userID); err != nil {
-			applog.App("api.Server", "recordAuthResult").Error("mark garmin connected", "user_id", userID, "error", err)
+			applog.App().Error("mark garmin connected", "user_id", userID, "error", err)
 		}
 	}
 }

backend/internal/api/server.go

@@ -177,7 +177,8 @@ func loggingMiddleware(next http.Handler) http.Handler {
 		}
 		slog.Default().LogAttrs(r.Context(), level, "",
 			slog.String("type", "http"),
-			slog.String("class", "api"),
+			slog.String("package", "api"),
+			slog.String("file", "server.go"),
 			slog.String("method", "loggingMiddleware"),
 			slog.String("http_method", r.Method),
 			slog.String("path", r.URL.Path),
@@ -256,7 +257,7 @@ func (s *Server) removeUserClient(userID int64) {
 
 	if ok {
 		if err := client.Close(); err != nil {
-			applog.App("api.Server", "removeUserClient").Error("close garmin client for deleted user", "user_id", userID, "error", err)
+			applog.App().Error("close garmin client for deleted user", "user_id", userID, "error", err)
 		}
 	}
 	if s.ClientConfig.TokenStorePath == "" {
@@ -264,7 +265,7 @@ func (s *Server) removeUserClient(userID int64) {
 	}
 	tokenStoreDir := filepath.Join(s.ClientConfig.TokenStorePath, strconv.FormatInt(userID, 10))
 	if err := os.RemoveAll(tokenStoreDir); err != nil {
-		applog.App("api.Server", "removeUserClient").Error("remove token store dir for deleted user", "user_id", userID, "error", err)
+		applog.App().Error("remove token store dir for deleted user", "user_id", userID, "error", err)
 	}
 }
 
@@ -311,7 +312,7 @@ func (s *Server) backgroundSync(userID int64, fn func(ctx context.Context) error
 			s.mu.Unlock()
 		}()
 		if err := fn(context.Background()); err != nil {
-			applog.App("api.Server", "backgroundSync").Error("background sync failed", "user_id", userID, "error", err)
+			applog.App().Error("background sync failed", "user_id", userID, "error", err)
 		}
 	}()
 	return true
@@ -331,7 +332,7 @@ func writeJSON(w http.ResponseWriter, status int, v any) {
 	w.Header().Set("Content-Type", "application/json")
 	w.WriteHeader(status)
 	if err := json.NewEncoder(w).Encode(v); err != nil {
-		applog.App("api", "writeJSON").Error("encode response", "error", err)
+		applog.App().Error("encode response", "error", err)
 	}
 }
 

backend/internal/api/session.go

@@ -64,7 +64,7 @@ func (s *Server) handleSessionLogin(w http.ResponseWriter, r *http.Request) {
 func (s *Server) handleSessionCallback(w http.ResponseWriter, r *http.Request) {
 	txnCookie, err := r.Cookie(auth.TxnCookieName)
 	if err != nil {
-		applog.App("api.Server", "handleSessionCallback").Warn("missing txn cookie", "error", err)
+		applog.App().Warn("missing txn cookie", "error", err)
 		http.Redirect(w, r, s.SessionConfig.FrontendURL+"/?auth_error=failed", http.StatusFound)
 		return
 	}
@@ -72,14 +72,14 @@ func (s *Server) handleSessionCallback(w http.ResponseWriter, r *http.Request) {
 
 	txn, err := auth.ParseTxnCookie(txnCookie, s.SessionConfig.Secret)
 	if err != nil {
-		applog.App("api.Server", "handleSessionCallback").Warn("failed to parse txn cookie", "error", err)
+		applog.App().Warn("failed to parse txn cookie", "error", err)
 		http.Redirect(w, r, s.SessionConfig.FrontendURL+"/?auth_error=failed", http.StatusFound)
 		return
 	}
 
 	result, err := s.Auth.HandleCallback(r.Context(), txn, r.URL.Query())
 	if err != nil {
-		applog.App("api.Server", "handleSessionCallback").Error("callback failed (state mismatch, code exchange, or ID-token verification)", "error", err)
+		applog.App().Error("callback failed (state mismatch, code exchange, or ID-token verification)", "error", err)
 		http.Redirect(w, r, s.SessionConfig.FrontendURL+"/?auth_error=failed", http.StatusFound)
 		return
 	}

backend/internal/api/setup.go

@@ -195,10 +195,10 @@ func (s *Server) handleSetupComplete(w http.ResponseWriter, r *http.Request) {
 		// on, and os.Rename refuses to replace a non-empty directory. The
 		// just-validated setup session must win, so clear the target first.
 		if err := os.RemoveAll(newDir); err != nil {
-			applog.App("api.Server", "handleSetupComplete").Error("remove stale token store dir", "user_id", userID, "error", err)
+			applog.App().Error("remove stale token store dir", "user_id", userID, "error", err)
 		}
 		if err := os.Rename(oldDir, newDir); err != nil && !os.IsNotExist(err) {
-			applog.App("api.Server", "handleSetupComplete").Error("rename setup token store dir", "user_id", userID, "error", err)
+			applog.App().Error("rename setup token store dir", "user_id", userID, "error", err)
 		}
 	}