Gateway authentication, credentials, and fetch-interceptor boundaries

Gateway authentication uses only x-lore-gateway-token; provider bearer or API-key headers never authorize Lore. Remote access fails closed without an exact configured-token match. Strip the gateway token before parsing and never forward, log, store, expose in URLs, or pass it via CLI arguments. Bind administrator extra headers only to configured provider and worker bases. Caller-selected origins receive no credentials and require the normalized-HTTPS allowlist, which rejects credentials, paths, queries, fragments, wildcards, and duplicates. The fetch interceptor must not reroute gateway-bound or localhost requests, but must still observe direct-gateway headers. Preserve authorization, API keys, bodies, and upstream URL/path metadata, share header construction across routing paths, and fail safely when URL or protocol detection is uncertain.