[iterate-2G] db16cyc spin-hint cooperative yield: unblock title-screen 0x10a0 gate

The silph title state machine (tid13) blocked on event 0x10a0, never signaled.
Root: the event's producer chain runs on the silph worker (entry 0x821C4AD0,
our tid14), which was starved. tid14 shares a HW slot with a guest spinlock/
barrier participant (sub_824D1328, entry 0x824D2940) that busy-spins on the
db16cyc hint `or r31,r31,r31` (encoding 0x7FFFFB78) at 0x824D140C. Under our
round-robin lockstep the spinner consumed its whole block every round and
starved the co-located tid14 (only 9 progress hits over 200M instr) — so the
producer never reached the event-create/duplicate/signal dance the canary
oracle performs (handle F80000E8 set by the submitter F8000044 via a duplicated
handle).

Fix (canary-faithful): recognize the db16cyc spin hint exactly as canary's
InstrEmit_orx does (code 0x7FFFFB78 -> DelayExecution) and surface it as a new
StepResult::Yield. The scheduler's yield_current() promotes every Ready peer on
the slot past STARVE_LIMIT so begin_slot_visit picks one next round, then they
reset and the spinner reclaims the slot — fair alternation, no priority
inversion, pure function of slot state (deterministic).

Result (lockstep, cache-persist, -n 200M): tid14 progresses past its old stall
into a real wait; tid13 advances off 0x10a0 to a new event; hub/submitter
re-enter their wait loops. imports 280k->592k, packets 124M->164M, swaps 1->2.
draws still 0 (the splash's first draw is a further-upstream gate).

Determinism preserved (two cold n50m runs byte-identical). n50m golden
re-baselined (imports 90296->339766, swaps 1->2; draws unchanged 0). n2m
golden unchanged (db16cyc not reached in first 2M). Tests 670/670.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

audit-runs/audit-059-handle-disambiguation/round35-lockstep-inflate/diff.out

@@ -0,0 +1,52 @@
+=== Fire counts ===
+  ours:   3
+  canary: 7
+
+=== Per-LR breakdown ===
+  ours:
+    lr=0x82458674: 3
+  canary:
+    lr=0x82457bd4: 2
+    lr=0x82458674: 5
+
+=== Side-by-side first 5 fires (entry registers) ===
+
+--- fire #0 ---
+  ours:   tid=6   cycle=363        lr=0x82458674 r3=0x40ba9ac0
+          dump: 419fecda 000007f6 00000000 41d7dd10 00001688 00000000 00000000 41f5dd80 82457958 823f53f0 00000000 00000000 00000001 00000000 00000000 4024a5c0
+  canary: tid=11  cycle=<unk>      lr=0x82458674 r3=0xbccc4ac0 r4=0x00000000 r5=0x00000001 r6=0x00000001 r7=0x00000000
+          dump: bdb19cda 000007f6 00000000 bde98d10 00001688 00000000 00000000 be078d80 82457958 823f53f0 00000000 00000000 00000001 00000000 00000000 bc365760
+
+--- fire #1 ---
+  ours:   tid=6   cycle=140548     lr=0x82458674 r3=0x40ba9b80
+          dump: 42c0f09a 00018ff6 00000000 43777210 0004d055 00000000 00000000 41f60d80 82457958 823f53f0 00000000 00000000 00000001 00000000 00000000 4024a960
+  canary: tid=11  cycle=<unk>      lr=0x82458674 r3=0xbccc4b80 r4=0x00000000 r5=0x00000001 r6=0x00000001 r7=0x00000000
+          dump: bed2a09a 00018ff6 00000000 bf892210 0004d055 00000000 00000000 be07bd80 82457958 823f53f0 00000000 00000000 00000001 00000000 00000000 bc365840
+
+--- fire #2 ---
+  ours:   tid=6   cycle=5957876    lr=0x82458674 r3=0x40ba9b80
+          dump: 419fecda 000007f6 00000000 414f5f70 000003b9 00000000 00000000 41f60d80 82457958 823f53f0 00000000 00000040 00000001 00000000 00000000 4024a980
+  canary: tid=11  cycle=<unk>      lr=0x82458674 r3=0xbccc4b80 r4=0x00000000 r5=0x00000001 r6=0x00000001 r7=0x00000000
+          dump: bdb19cda 000007f6 00000000 bd610b90 000003b9 00000000 00000000 be07bd80 82457958 823f53f0 00000000 00000040 00000001 00000000 00000000 bc365860
+
+--- fire #3 ---
+  ours:   <no fire>
+  canary: tid=11  cycle=<unk>      lr=0x82458674 r3=0xbccc5300 r4=0x00000000 r5=0x00000001 r6=0x00000001 r7=0x00000000
+          dump: bdb1acda 000007f6 00000000 bce24ed0 00000167 00000000 00000000 be07bd80 82457958 823f53f0 00000000 00000000 00000001 00000000 00000000 bc365f40
+
+--- fire #4 ---
+  ours:   <no fire>
+  canary: tid=6   cycle=<unk>      lr=0x82457bd4 r3=0x701cf3c0 r4=0x00000004 r5=0x00002530 r6=0x00008000 r7=0x00000001
+          dump: be95af9a 0000c170 00000000 b2050010 000681e9 00000000 00000000 be07bd80 82457958 823f53f0 00000000 0000c17a 00000001 701cf4e0 00000000 be95af90
+
+=== Equivalence check: u32 lanes at +0x04 and +0x10 (work-item magic + counter) ===
+  Both fields are stable identifiers across engines (host VAs differ but data should match).
+
+  Index of fields:
+    [+0x04] = work-item 'size?' (looks like a length field)
+    [+0x10] = state counter (per round 30, this is [+128/4 ?]) — but in dump it's u32[4]
+
+  ours [+04,+10]:   [(2038, 5768), (102390, 315477), (2038, 953)]
+  canary [+04,+10]: [(2038, 5768), (102390, 315477), (2038, 953), (2038, 359), (49520, 426473), (232195, 999643), (6134, 13763)]
+
+  ours fires whose [+04,+10] match a canary fire: 3/3