Route process calls directly to browser VMs

[tnsardesai]

summary

• add process to the default direct-to-VM browser routing allowlist
• cover process exec, spawn, kill, resize, status, stdin, and stdout streaming through the existing prefix matcher
• keep fs/* and telemetry/events on the control plane and preserve the environment override/kill switch

testing

• pytest (678 passed, 2952 skipped)
• ruff check and ruff format --check on touched files
• live browser validation: exec, spawn, and stdout streaming routed through /browser/kernel/process/... and returned the expected output