ITERATE-2.V: scheduler priority aging closes 18-day AUDIT-049 wedge

Priority aging in xenia-cpu/scheduler.rs:pick_runnable
(effective_priority = base + age_bonus(now_round - last_run_round),
capped at +31, AGING_ROUNDS_PER_BONUS=1). Strict-priority was parking
priority=0 threads behind CPU-bound priority=15 audio mixer
(sub_824D1328 guest spinwait at PC=0x824d1404 on CPU5). Aging
eventually picks the starved thread, breaking the producer-consumer
cycle that caused 5-tid wedge at PC=0x824ac578 since AUDIT-049 (10 May).

Cascade observed: tid=13 clean exit; events 121K -> 13M (107x); last
host_ns 767ms -> 51,011ms (66x); 8 new threads spawn; VdSwap 1 -> 2.

Complete two-day iterate sequence (2026-05-27 -> 2026-05-28):
- 2.F: VdSwap drain timeout 900ms -> 1ms (xenia-gpu/handle.rs); 876x
       perf win on VdSwap kernel callback
- 2.H: vA0000000 physical heap bucket added (state.rs, exports.rs);
       ctx_ptrs now in 0xA0000000-0xBFFFFFFF range matching canary
- 2.L: Phase-A diff harness categorized [return_value mismatch],
       [status mismatch], [args_resolved.path mismatch] tags
       (tools/diff-events/diff_events.py); closes reading-error #41
       (silent test-harness state leak invalidating trace diffs)
- 2.M: always-on exit-thread-state.json sibling to Phase-A JSONL
       (event_log.rs + xenia-app/main.rs); closes reading-error #42
       (Phase-A blind to blocked-forever waits)
- 2.Q: signal.match kernel instrumentation in NtSetEvent /
       NtReleaseSemaphore / KeSetEvent / KeReleaseSemaphore
       (exports.rs); emits target_handle + waiter_count + waiter_tids
- 2.T: wake.requested kernel instrumentation in wake_eligible_waiters
       (exports.rs); emits target_tid + transition + new_state
- 2.V: scheduler priority aging (xenia-cpu/scheduler.rs) [keystone]

Plus accumulated WIP from earlier May (contention_manifest,
phase_b_snapshot, xam/xaudio enhancements, analysis db, xex loader,
xenia-app main loop, etc.). Audit-runs/ artifacts remain untracked
per project convention.

Tests: 300 xenia-cpu / 227 xenia-kernel / 5 xenia-app / 19 xenia-path
/ 30+ smaller suites -- all PASS, 0 regressions. Determinism preserved
(2x cold runs bit-identical at 13,003,881 events post-2.V).

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

docs/functions/sub_82457EF0.md

@@ -0,0 +1,47 @@
+---
+address: 0x82457EF0
+classification: thread_proc
+confidence: high
+last_audit: 060
+aliases:
+  - "tid=6 thread_proc"
+---
+
+# sub_82457EF0 — tid=6 thread_proc (worker entry)
+
+## Synopsis
+
+Thread procedure for tid=6 in ours. 0 static callers — and that is *correct* for a `thread_proc`: it is installed as an entry-point via `ExCreateThread` somewhere in boot, not invoked via `bl`. AUDIT-059's "only-caller of [sub_82458B90](sub_82458B90.md) has 0 callers — fnptr-array only" inference was wrong; the actual activation is thread creation.
+
+## Evidence
+
+- AUDIT-060 Probe O ours: fires **1× on tid=6** (HW=2, cycle=0, lr=`0xbcbcbcbc` — thread-entry sentinel).
+- `lr=0xbcbcbcbc` is the Xbox 360 / xenia convention for "this is the very first instruction of a thread proc; no return address". This is a diagnostic that distinguishes thread entry from a normal `bl` fire.
+- Calls [sub_82458B90](sub_82458B90.md) at `+0x24` (1 callee at this offset).
+
+## Activation
+
+Registered as a thread entry-point via `ExCreateThread` (or similar). The caller of `ExCreateThread` that installs this entry has not yet been traced — that's the *real* activation site, and tracing it would close the loop on tid=6's purpose. Once tid=6 starts, the OS scheduler runs `sub_82457EF0` from PC `0x82457EF0` with LR=`0xbcbcbcbc`.
+
+## Static graph
+
+- Static callers (`bl`): **0** (correct — see classification).
+- Callees: `bl sub_82458B90` at `+0x24` (PC `0x82457F18`).
+- The "indirect call site" that activates this fn is the `ExCreateThread` invocation, captured at runtime, not in static `xrefs`.
+
+## Audit log
+
+- **AUDIT-060 (2026-05-12)** — identified as tid=6 thread_proc via `lr=0xbcbcbcbc` thread-entry sentinel + HW=2 + cycle=0 first-fire context. AUDIT-059's static-reachability inference invalidated. [confirmed]
+- **AUDIT-059 (2026-05-11)** — flagged as "only-caller of canary signaler A; 0 callers — fnptr-array only". [STATUS: partially correct (0 callers true; fnptr-array WRONG), corrected by AUDIT-060 — it's a thread_proc.]
+
+## Open questions
+
+- Where is `ExCreateThread(entry=sub_82457EF0, ...)` called from? Probe the `ExCreateThread` import thunk in both engines with filtered LR/r3 to find the install site.
+- What does the thread body do beyond calling [sub_82458B90](sub_82458B90.md) once? Likely it's a loop that waits on a queue, dequeues work, and signals completion via the bl at `+0x24`. Disassemble the body.
+
+## Cross-references
+
+- Thread-body callee: [sub_82458B90](sub_82458B90.md).
+- Install site (`ExCreateThread` caller): not yet identified.
+- Audits: 059, 060.
+- Artifacts: `audit-runs/audit-060-fnptr-array-bootstrap/ours-phase1.stdout` (the `lr=0xbcbcbcbc` sentinel evidence).