release: adopt pi 0.84.4 + pi-atelier v0.10.0, and fix the doc claim the pi bump invalidates

pi 0.84.3 -> 0.84.4 (no Breaking Changes / Removed heading in that section,
grepped). Adopted for three fixes that land on machinery this fleet runs:
#6879 (large tool results crossing the auto-compaction threshold were sent to
the provider before compacting), #8345 (a resumed session corrupted its next
appended entry when the JSONL lacked a trailing newline -- that file is the
memory feeder's input; measured 49/49 clean here beforehand), and #8537
(triggerTurn:false messages sent mid-run were inserted between a tool call and
its result). The mempalace mailbox is outside #8537's precondition: it delivers
at agent_settled with deliverAs:"steer" and no triggerTurn, and 0.84.4 leaves
the documented steer semantics unchanged.

pi-atelier v0.8.2 -> v0.10.0: two minor releases, both UI-only, no BREAKING
notice. v0.9.0 raises its minimum pi to 0.84.0 and, unlike the
0.7.1-under-pi-0.84 startup-hang precedent, encodes it in peerDependencies
(>=0.84.0). Satisfied by PI_VERSION=0.84.4. Both executable floors compare with
sort -V, so 0.10.0 >= 0.7.1 evaluates correctly.

docs/observational-memory.md: pi's own compaction.md gained one paragraph in
0.84.4 -- autoCompact is now also checked mid-run, after a tool batch's results
are appended. Our text said compaction is checked only when pi goes idle and so
"never interrupts a turn"; that was only ever true of the OM trigger. The
section now states both entry points into session_before_compact and the
diagram carries the second edge (mermaid checker re-run: 6 blocks, 44 labels,
0 soft-wrapped, no cut glyphs at 1280px and 800px).

README: the version-pin table had been wrong since v1.8.6 -- 93f986e moved
ARG PI_VERSION to 0.84.3 and MEMPALACE_VERSION to 3.8.0 and neither table row,
so it advertised pi 0.84.2 / mempalace 3.7.1. Corrected, plus the
--expected-version example that would now fail against a 0.84.4 image.

CHANGELOG: Unreleased retitled v1.8.12 (2026-08-31) with the audits above and a
dependency-audit table -- every other component measured SAME (skillset
snapshot --check OK at a12fe5e, 0 commits since baked).

docs/observational-memory.md

@@ -21,8 +21,9 @@ palace, see
 > Verified on pi-devbox **v1.8.9** (`release_tag v1.8.9`, source `aac4a1c`),
 > which bakes pi-observational-memory **v3.0.4** at commit `ce9fc98` — the value
 > in `/etc/pi-devbox/build-manifest.json` → `components.pi-observational-memory`.
-> Every number below was read from that tree, from pi 0.84.3's own docs, or from
-> the live container.
+> Every number below was read from that tree, from pi's own docs, or from the
+> live container. The pi-side mechanics were first read at pi **0.84.3** and
+> re-checked at **0.84.4** (v1.8.12), which moved one of them — see §3.
 
 ---
 
@@ -93,6 +94,7 @@ flowchart TD
     S(["agent_settled"]) --> C{"81k tokens<br/>since compacting?"}
     C -- yes --> CP["ctx.compact()"]
     CP --> H(["session_before_compact"])
+    A(["pi autoCompact<br/>idle, or mid-run<br/>after a tool batch"]) --> H
     H --> F["fold the ledger<br/>no model call"]
     F --> VIS["compacted memory"]
 ```
@@ -105,10 +107,16 @@ flowchart TD
   a *successful same-turn* reflection **and** an active pool above
   `observationsPoolTargetTokens` [10000]. Not a third worker on a third
   threshold.
-- **compaction** — `compactAfterTokens` [81000], checked when pi goes idle, so it
-  never interrupts a turn. Pi will also compact on its own when the context is
-  nearly full (`contextTokens > contextWindow - reserveTokens`, `reserveTokens`
-  [16384]).
+- **compaction** — `compactAfterTokens` [81000], checked at `agent_settled`, so
+  *this* trigger never interrupts a turn. Pi will also compact on its own when
+  the context is nearly full (`contextTokens > contextWindow - reserveTokens`,
+  `reserveTokens` [16384]), and **from pi 0.84.4 that check also runs mid-run** —
+  after a tool batch's results are appended, before the next assistant response,
+  skipped only when the batch ends the run and no queued message needs another
+  response. So `session_before_compact` has **two** entry points and the second
+  one can fire *inside* a turn. Harmless for the fold itself, which makes no
+  model call, but worth stating plainly: "never interrupts a turn" was only ever
+  true of the observational-memory trigger, and reads as a promise about pi's.
 
 ## 4. What compaction actually does to your context