fix: read GOOGLE_SHEETS_ID and default range to current-year tab

LoadConfig read SPREADSHEET_ID, but the .env defines GOOGLE_SHEETS_ID,
so config loading failed. The default SHEET_RANGE was also a hardcoded
'Dyżury!A1:F100', but the spreadsheet tabs are named per year (e.g.
'2026'), producing a 400 'Unable to parse range'. Read GOOGLE_SHEETS_ID
and derive the default range from the current year.

Add a RUN_LIVE-gated integration test that drives the full
LoadConfig -> Service -> Syncer.Sync -> Store path against the live
Sheet, and gitignore the generated rota.json cache.

.gitignore

@@ -1 +1,2 @@
 .env
+rota.json

live_test.go

@@ -0,0 +1,50 @@
+package dyzurbot
+
+import (
+	"context"
+	"os"
+	"path/filepath"
+	"testing"
+)
+
+// TestLiveFetch exercises the full production path — LoadConfig reads the
+// environment/.env, NewService wires the Store + Syncer, and Syncer.Sync hits
+// the live Google Sheets API, parses the result, and persists it to the cache
+// file via Store.Replace. The resulting JSON is left on disk (CachePath,
+// default rota.json) for inspection.
+//
+// It is skipped unless RUN_LIVE=1, so the normal `go test ./...` run stays
+// offline and fast.
+//
+//	RUN_LIVE=1 go test -run TestLiveFetch -v .
+//
+// Requires GOOGLE_API_KEY and GOOGLE_SHEETS_ID in the environment/.env.
+func TestLiveFetch(t *testing.T) {
+	if os.Getenv("RUN_LIVE") != "1" {
+		t.Skip("set RUN_LIVE=1 to run the live Google Sheets fetch")
+	}
+
+	cfg, err := LoadConfig()
+	if err != nil {
+		t.Fatalf("LoadConfig: %v", err)
+	}
+	t.Logf("config: spreadsheet=%s range=%q cache=%s",
+		cfg.SpreadsheetID, cfg.SheetRange, cfg.CachePath)
+
+	svc := NewService(cfg)
+	if err := svc.Syncer.Sync(context.Background()); err != nil {
+		t.Fatalf("sync: %v", err)
+	}
+
+	rota, lastSynced := svc.Store.Snapshot()
+	t.Logf("synced %d weeks, %d people at %s",
+		len(rota.Weeks), len(rota.People), lastSynced.Format("2006-01-02 15:04:05"))
+
+	// Confirm the JSON actually landed on disk and show where.
+	written, err := os.ReadFile(cfg.CachePath)
+	if err != nil {
+		t.Fatalf("read cache %q: %v", cfg.CachePath, err)
+	}
+	abs, _ := filepath.Abs(cfg.CachePath)
+	t.Logf("wrote cache JSON (%d bytes) to %s", len(written), abs)
+}

service.go

@@ -22,13 +22,17 @@ type Config struct {
 func LoadConfig() (Config, error) {
 	_ = godotenv.Load()
 
+	// Default range targets the current year's tab (sheets are named per year,
+	// e.g. "2026"), matching the spreadsheet layout.
+	defaultRange := fmt.Sprintf("%d!A1:F100", time.Now().Year())
+
 	cfg := Config{
-		SpreadsheetID: os.Getenv("SPREADSHEET_ID"),
-		SheetRange:    getenvDefault("SHEET_RANGE", "Dyżury!A1:F100"),
+		SpreadsheetID: os.Getenv("GOOGLE_SHEETS_ID"),
+		SheetRange:    getenvDefault("SHEET_RANGE", defaultRange),
 		CachePath:     getenvDefault("ROTA_CACHE_PATH", "rota.json"),
 	}
 	if cfg.SpreadsheetID == "" {
-		return Config{}, fmt.Errorf("missing SPREADSHEET_ID in environment/.env")
+		return Config{}, fmt.Errorf("missing GOOGLE_SHEETS_ID in environment/.env")
 	}
 
 	raw := getenvDefault("SYNC_INTERVAL", "30m")

service_test.go

@@ -1,12 +1,13 @@
 package dyzurbot
 
 import (
+	"fmt"
 	"testing"
 	"time"
 )
 
 func TestLoadConfigDefaults(t *testing.T) {
-	t.Setenv("SPREADSHEET_ID", "sheet-123")
+	t.Setenv("GOOGLE_SHEETS_ID", "sheet-123")
 	t.Setenv("SHEET_RANGE", "")
 	t.Setenv("ROTA_CACHE_PATH", "")
 	t.Setenv("SYNC_INTERVAL", "")
@@ -18,8 +19,9 @@ func TestLoadConfigDefaults(t *testing.T) {
 	if cfg.SpreadsheetID != "sheet-123" {
 		t.Errorf("SpreadsheetID: got %q", cfg.SpreadsheetID)
 	}
-	if cfg.SheetRange != "Dyżury!A1:F100" {
-		t.Errorf("SheetRange default: got %q", cfg.SheetRange)
+	wantRange := fmt.Sprintf("%d!A1:F100", time.Now().Year())
+	if cfg.SheetRange != wantRange {
+		t.Errorf("SheetRange default: got %q, want %q", cfg.SheetRange, wantRange)
 	}
 	if cfg.CachePath != "rota.json" {
 		t.Errorf("CachePath default: got %q", cfg.CachePath)
@@ -30,14 +32,14 @@ func TestLoadConfigDefaults(t *testing.T) {
 }
 
 func TestLoadConfigRequiresSpreadsheetID(t *testing.T) {
-	t.Setenv("SPREADSHEET_ID", "")
+	t.Setenv("GOOGLE_SHEETS_ID", "")
 	if _, err := LoadConfig(); err == nil {
-		t.Fatal("expected error when SPREADSHEET_ID is missing")
+		t.Fatal("expected error when GOOGLE_SHEETS_ID is missing")
 	}
 }
 
 func TestLoadConfigRejectsBadInterval(t *testing.T) {
-	t.Setenv("SPREADSHEET_ID", "sheet-123")
+	t.Setenv("GOOGLE_SHEETS_ID", "sheet-123")
 	t.Setenv("SYNC_INTERVAL", "not-a-duration")
 	if _, err := LoadConfig(); err == nil {
 		t.Fatal("expected error for unparseable SYNC_INTERVAL")
@@ -45,7 +47,7 @@ func TestLoadConfigRejectsBadInterval(t *testing.T) {
 }
 
 func TestLoadConfigRejectsNonPositiveInterval(t *testing.T) {
-	t.Setenv("SPREADSHEET_ID", "sheet-123")
+	t.Setenv("GOOGLE_SHEETS_ID", "sheet-123")
 	t.Setenv("SYNC_INTERVAL", "0s")
 	if _, err := LoadConfig(); err == nil {
 		t.Fatal("expected error for non-positive SYNC_INTERVAL")