'Teleport relay' fork-safety refinements: forkDirectLines and tools-baseline fingerprint

Claude Code has an internal "teleport relay" mechanism related to prompt caching (a way of reusing previously processed prompt content to save time and cost) that comes into play when a session is forked. New bookkeeping was added to it:

• A boot-time check arms or disables the relay based on whether a cache marker is present, logging a message like "prompt-cache relay stays off: boot had no marker" and firing telemetry events upgrade_teleport_cache and cli_teleport_arm_verdict.
• Tracking of which forked request lines went "direct" (bypassing the relay), so later requests on the same fork skip the relay too.
• A comparison of a captured tools baseline's model and fingerprint, to determine whether a forked request's tool set is still "intact" or has "changed".