perf: index routing snapshots and quota usage

AUDIT.md

@@ -64,11 +64,17 @@ released agent, or reject a valid completion.
 
 ## P2 — performance
 
-- Cache/parallelise health probes; schedule from one task/worker snapshot.
-  Current routing repeatedly scans tasks and probes candidates per queued task.
-- Index active leases and quota windows. Do not scan the whole event log per
-  availability check or rewrite the full task snapshot after every event.
-- Add 1k/10k-task benchmarks with assignment and append p95 budgets.
+- **Closed 2026-07-30.** Each scheduling pass takes one atomic task/lease
+  snapshot, batches cached (TTL) reachability probes concurrently, and
+  evaluates candidate availability once. It no longer probes candidates or
+  scans active tasks once per queued task.
+- **Closed 2026-07-30.** Active leases and per-harness, time-ordered quota
+  receipts are projection indexes. Availability uses indexed rolling-window
+  sums rather than decoding the event log; the task snapshot is a one-time
+  disposable compatibility cache rather than a full rewrite on every append.
+- **Closed 2026-07-30.** `BenchmarkAssignPending{1K,10K}` and
+  `BenchmarkAppend{1K,10K}` report and enforce p95 budgets, with durable
+  fsync cost included in their respective paths.
 
 ## Delivery order