docs: reserve R18 for hook resilience

Author: myobie

docs/vrs/requirements.md

@@ -91,7 +91,7 @@ accepted.
 - **R17 Durable error propagation:** Lifecycle, harness/eval, provider-turn,
   task/exec/PTY, hook, and delivery errors are durably reported to the
   responsible supervisor with agent/task identity and actionable context.
-- **R18 Targeted reconciliation:** An exact agent/task selector resolves its
+- **R19 Targeted reconciliation:** An exact agent/task selector resolves its
   identity and pinned host before mutation; unknown, ambiguous, and wrong-host
   targets refuse before writes, listing, or actions. Materialization, hook
   gates, PTY inspection, and plan execution are limited to the selected