chore(GWC-31): relabel perf-pass GWC-3x comments to PERF-nn; tracker housekeeping

Sweep code/doc comments citing unregistered GWC-30/GWC-31 (2026-08-15 perf
pass) to PERF-02/PERF-07/PERF-22, keyed to task numbers in
docs/plans/2026-08-15-perf-review-remediation.md; add a PERF-ID register
table to that plan. Genuine cycle-2 GWC-30 citations (gateway-side frame-
reader 4-byte prefix fix in Server/Workers/WorkerFrameReader.cs and its
test) are left untouched.

Add a line to REVIEW-PROCESS.md reserving the GWC/WRK/IPC/SEC/CLI/TST
prefixes for the archreview domain registers.

Tracker housekeeping per archreview/2026-08-19/00-overall.md:
- GWC-16 -> Won't fix (rationale: PERF(followup) comment documents the
  double session lookup as measured-negligible, deliberately not collapsed)
- IPC-08 -> Done (closed by 7c1ea12/a1a38b5; residual tracked as IPC-34)
- IPC-31 -> Done (superseded by GWC-28's write-time sequence stamping)
- TST-06, TST-17 rows refreshed per cycle-3 60-testing-docs-gaps.md
- WRK-31 (and defensively WRK-29/30) registered as reserved/do-not-reuse
  interim IDs burned by e913dab, in both the cycle-2 tracker and the
  cycle-2 worker remediation doc

Flip Batch C to Done in archreview/2026-08-19/remediation/00-tracking.md.

Worker-side files (Worker/Ipc/WorkerFrameReader.cs, WorkerFrameWriter.cs)
are comment-only edits, unverified here (net48 x86, windev-only build).

src/ZB.MOM.WW.MxGateway.Tests/Metrics/GatewayMetricsTests.cs

@@ -19,7 +19,7 @@ public sealed class GatewayMetricsTests
         metrics.CommandFailed("WriteSecured", "AuthorizationFailed", TimeSpan.FromMilliseconds(12));
         metrics.EventReceived("session-1", "OnDataChange");
         metrics.EventReceived("session-1", "OnDataChange");
-        // GWC-30: the worker queue-depth gauge sums one live source per worker client, so the two
+        // PERF-02: the worker queue-depth gauge sums one live source per worker client, so the two
         // registrations below stand in for two concurrent sessions holding 3 and 4 events.
         using IDisposable workerDepthSourceA = metrics.RegisterWorkerEventQueueDepthSource(static () => 3);
         using IDisposable workerDepthSourceB = metrics.RegisterWorkerEventQueueDepthSource(static () => 4);
@@ -58,7 +58,7 @@ public sealed class GatewayMetricsTests
     }
 
     /// <summary>
-    ///     GWC-30: the worker queue-depth gauge sums every registered source rather than holding a
+    ///     PERF-02: the worker queue-depth gauge sums every registered source rather than holding a
     ///     single pushed scalar, so concurrent sessions add up instead of overwriting one another,
     ///     and a disposed registration (a worker client going away) drops out of the sum. Disposal
     ///     is idempotent because a client's dispose path can run twice.