Baseline benches and counters for the view work (V1)

Part of epic #305.

Problem. No bench measures the cost of a write vs graph size, rule count and subscriber count, and no counter tells whether a read of a deployed rule evaluated it. The review's numbers (report Section 4) came from an ad-hoc harness.

Target. (a) perf-gate views: the Section 4 matrix (10k/100k/1M edges; unbound/keyed subscribers 1/10/100/1,000; recursive and non-recursive views; 200-rule catalog) as a perf-gate scenario with p50/p99 write->delta, ack, ad-hoc read during writes, server CPU per write and RSS; (b) a criterion bench of the maintained-view micro-benchmark (report A.7) as the headroom reference; (c) counters view_reads, rule_evaluations, view_maintenance_us exported on /metrics/prometheus.

Acceptance. make bench-views-remote runs under the shared lock and reproduces the Section 4 tables within noise; rule_evaluations increments once per deployed-rule read today (so V9 can assert 0); the bench is wired into full-suite.yml as perf-gate-only.

Size M. Dependencies none. Order slot 1.

feat(perf-gate): views benchmark of write and read cost against deplo…