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 Done (superseded by GWC-28's write-time sequence stamping)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).

REVIEW-PROCESS.md

@@ -79,6 +79,12 @@ Add one entry per finding to the `## Findings` section of the module's
 
 - **Finding ID** — `<Module>-NNN`, numbered sequentially within the module and
   never reused (e.g. `Worker-001`). IDs are permanent even after resolution.
+  The `GWC`/`WRK`/`IPC`/`SEC`/`CLI`/`TST` prefixes are reserved for the
+  `archreview/` domain registers (a separate, whole-repo review series with its
+  own tracking documents) — never assign one of these prefixes to a
+  `code-reviews/` finding, and any other work stream (perf passes, ad hoc
+  remediation plans, etc.) that wants a stable per-item ID must mint its own
+  distinct prefix rather than borrowing one of these six.
 - **Severity:**
   - **Critical** — data loss, security breach, crash/deadlock, or outage.
   - **High** — incorrect behaviour with significant impact; no safe workaround.