Naming, layout and comments: descriptive full-word names, one item per line in wrapped calls and literals, and doc comments on exported names

Short and single-letter names in application code become full words (tests
keep theirs). Wrapped calls, signatures and composite literals put one item
per line, and one-line function bodies are expanded. Exported names and
groups of constants get doc comments, and comments refer to the renamed
identifiers.

internal/fetcher/worker_findatender.go

@@ -15,9 +15,12 @@ import (
 // runFindAOpportunity polls Find a Tender every configured interval until ctx
 // is cancelled.
 func runFindAOpportunity(
-	ctx context.Context, logger *slog.Logger, conf *config.JobSearchConfig, since time.Time,
+	ctx context.Context,
+	logger *slog.Logger,
+	conf *config.JobSearchConfig,
+	since time.Time,
 ) error {
-	w := util.Worker{
+	worker := util.Worker{
 		Logger:   logger,
 		Name:     "FindAOpportunity",
 		Interval: conf.Sources.FindATender.Interval,
@@ -25,19 +28,26 @@ func runFindAOpportunity(
 			return fetchFindAOpportunity(ctx, logger, conf, since)
 		},
 	}
-	return w.Run(ctx, since)
+	return worker.Run(ctx, since)
 }
 
 // fetchFindAOpportunity fetches everything updated since since from Find a
 // Tender. Finding nothing returns ErrNoNewReleases, so the worker still moves
 // its checkpoint on.
 func fetchFindAOpportunity(
-	ctx context.Context, logger *slog.Logger, conf *config.JobSearchConfig, since time.Time,
+	ctx context.Context,
+	logger *slog.Logger,
+	conf *config.JobSearchConfig,
+	since time.Time,
 ) error {
 	opportunities, err := util.AwaitTask(ctx, func() ([]*types.Opportunity, error) {
-		ft := findatender.New(conf, conf.Sources.FindATender.APIRoot, findatender.WithLogger(logger))
-		defer ft.Shutdown()
-		return ft.With(ctx).FetchAll(since, true)
+		findATender := findatender.New(
+			conf,
+			conf.Sources.FindATender.APIRoot,
+			findatender.WithLogger(logger),
+		)
+		defer findATender.Shutdown()
+		return findATender.With(ctx).FetchAll(since, true)
 	})
 	if errors.Is(err, findatender.ErrNoReleases) {
 		return ErrNoNewReleases