fix(runner): harden catalogue scrape against 429s; disable sourcemap upload

- scraper.go: ScrapeCatalogue now uses retryGet (9 attempts, 10s base) +
  500–1500ms inter-page jitter instead of bare GetContent. ScrapeMetadata
  also switched to retryGet so a single 429 on a book page is retried rather
  than aborting the whole refresh.
- catalogue_refresh.go: per-book delay is now configurable
  (RUNNER_CATALOGUE_REQUEST_DELAY, default 2s) + up to 50% random jitter
  applied before every metadata fetch. Only metadata is scraped here —
  chapters are fetched on-demand, not during catalogue refresh. Progress
  logged every 50 books instead of 100.
- config.go / runner.go / main.go: add CatalogueRequestDelay field wired
  from RUNNER_CATALOGUE_REQUEST_DELAY env var.
- release.yaml: comment out upload-sourcemaps job and remove it from the
  release needs; GlitchTip auth token needs refreshing after DB wipe.

backend/internal/config/config.go

@@ -126,6 +126,11 @@ type Runner struct {
 	// is already indexed and a 24h walk would be wasteful.
 	// Controlled by RUNNER_SKIP_INITIAL_CATALOGUE_REFRESH=true.
 	SkipInitialCatalogueRefresh bool
+	// CatalogueRequestDelay is the base delay inserted between per-book metadata
+	// requests during a catalogue refresh. A random jitter of up to 50% is added
+	// on top. Defaults to 2s. Increase to reduce 429 pressure on novelfire.net.
+	// Controlled by RUNNER_CATALOGUE_REQUEST_DELAY (e.g. "3s", "500ms").
+	CatalogueRequestDelay time.Duration
 }
 
 // Config is the top-level configuration struct consumed by both binaries.
@@ -196,6 +201,7 @@ func Load() Config {
 			MetricsAddr:                 envOr("RUNNER_METRICS_ADDR", ":9091"),
 			CatalogueRefreshInterval:    envDuration("RUNNER_CATALOGUE_REFRESH_INTERVAL", 0),
 			SkipInitialCatalogueRefresh: envBool("RUNNER_SKIP_INITIAL_CATALOGUE_REFRESH", false),
+			CatalogueRequestDelay:       envDuration("RUNNER_CATALOGUE_REQUEST_DELAY", 2*time.Second),
 		},
 
 		Meilisearch: Meilisearch{