docs: record C4 route 4b-2 landing and its user-passed far-snap gate

Route 4b-2 landed at 7f1c1f5a and the two-client far-snap walk passed
(2026-08-04): a remote crossing 96 m in both directions stays visible and
correctly positioned at range and resumes smooth interpolation on the way in,
with no freeze, Z pop, vanish, or invisible-but-solid.

Records that #309 is still outstanding and why we know it: the
ACDREAM_PROBE_PARK=1 capture from the accepting session shows 11 parks, every
one cause=unplaceable and zero cause=quiescence, so the shared-core park change
has not been exercised live. That probe was added precisely because the prior
#309 steps could pass while broken — without it the session would have been
recorded as a full pass.

Also records the corrected 10,968 baseline and the two process lessons: the
round-1 defect traces to the contract omitting "and still advance the pose",
and the park defect should have been split into its own slice when it surfaced
in round 2 rather than riding inside 4b-2 for three more review rounds.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

docs/plans/2026-08-02-placement-cutover.md

@@ -314,6 +314,34 @@ same commit) → docs/handoff commit. No workarounds; no fused slices.
       deletions. 4b-1 stays a separate landing regardless: it is where the
       park-withdraws-the-entity failure mode is decided, and it must not be
       reviewed alongside a large deletion.
+    - **4b-2 LANDED at `7f1c1f5a` (2026-08-04); far-snap connected gate
+      USER-PASSED same day.** Four fix rounds, eight Opus reviews; the slice was
+      fully green at 10,990 / 10,997 / 11,004 while containing real defects
+      (a frozen remote pinned as correct by its own test; a fallback that
+      over-wrote on the exact retail paths that decline to store; a park guard
+      incomplete on two independent axes). Final suite 11,009 / 4 / 0 against a
+      **measured** 10,968 baseline — the 10,973 figure used earlier was wrong.
+      Its real yield was a defect under routes 1 and 2, not the far snap:
+      `ParkDeferred`'s quiescence parks withdrew the entity and were never
+      restorable while `Forget(restoreCancelledPark: true)` runs for every
+      accepted Position on every entity. The restorable decision now lives
+      inside `ParkDeferred` after `SnapToCell`, read against every live
+      quiescence.
+      **Still outstanding: #309.** The `ACDREAM_PROBE_PARK=1` capture from the
+      accepting session shows 11 parks, all `cause=unplaceable` — zero
+      quiescence-cause parks, so the shared-core park change is NOT yet
+      connected-verified. Without the probe that session would have been
+      recorded as a pass.
+      Process lesson recorded: the round-1 defect was caused by the contract
+      omitting "and still advance the pose", and the park defect should have
+      been split into its own slice the moment it surfaced in round 2 instead
+      of riding inside 4b-2 for three more rounds.
+      Findings chain:
+      [contract](../research/2026-08-04-c4-route-4b-2-contract.md) →
+      [round 1](../research/2026-08-04-c4-route-4b-2-review-findings.md) →
+      [round 2](../research/2026-08-04-c4-route-4b-2-delta-review-findings.md) →
+      [round 3](../research/2026-08-04-c4-route-4b-2-round3-correction.md) →
+      [round 4](../research/2026-08-04-c4-route-4b-2-round4-correction.md).
   Note the route-4 Create half is ALREADY DONE (C3b/C3c); the remaining work is
   steady-state remote Position plus the deletions. AP-131 is NOT retired by
   either sub-slice — see the scoping doc for why route 4 alone cannot.