Hardcode Firecrawl API endpoint, drop FIRECRAWL_ENDPOINT config

Firecrawl has a single public API at https://api.firecrawl.dev/v2.
The endpoint was configurable but never varied across environments,
so hardcode it as a package-level const and remove the Endpoint
field from FirecrawlConfig and all downstream wiring (bootstrap,
Helm chart, probod, vetting, cookiebanner).

Signed-off-by: Émile Ré <emile@probo.com>

pkg/probodconfig/config.go

@@ -49,8 +49,7 @@ type (
 
 	// FirecrawlConfig contains Firecrawl web scraping API configuration.
 	FirecrawlConfig struct {
-		Endpoint string `json:"endpoint"`
-		APIKey   string `json:"api-key"`
+		APIKey string `json:"api-key"`
 	}
 
 	// Config represents the probod application configuration.