docs: record the primary's real lineage — EMB-X1JY06WJ -> EMB-7KJ4VR4G -> synlig

Three docs said the primary was "seeded from EMB-7KJ4VR4G's palace", which is
true but stops one hop short. That palace was itself carried over from
EMB-X1JY06WJ, the previous work computer, when it was replaced around
2026-07-06.

Evidence, read read-only out of the frozen archive on EMB-7KJ4VR4G: 76 drawers
carry `source_machine=EMB-X1JY06WJ` and they are the oldest in the store --
earliest filed_at 2026-05-04, two months before that machine's stack existed --
with no other source_machine value present. The remaining ~16k were filed
locally afterwards (15,189 in July, 1,073 in August). Last write is
2026-08-14T15:07:06, the seed instant.

Two consequences, recorded in rfc-001 S4.4:

- It was the *second* whole-palace file copy, not the first, and both were
  single-source clones. So the method has two successes behind it and still
  zero exercises of merge semantics -- S7.6 is *less* tested than "we've done
  this twice" would suggest, not more.
- The primary now holds records from a machine that no longer exists, and
  `source_machine` is the only thing marking them. Not noise; don't prune it.

Also corrects a94eb7f, which inferred the archive's origin from the
`.devbox-owner` marker. That marker only records that the devbox adopted the
directory and says nothing about provenance -- the archive predates the stack.
And native pi on EMB-7KJ4VR4G is "not installed *yet*", a deferred hazard rather
than a closed one: a native install there would resolve its palace to
~/.mempalace, i.e. the frozen archive, and split that machine's memory from
central silently. Flip at install time.

docs/synlig-primary-runbook.md

@@ -5,7 +5,8 @@ on the primary, with verified evidence, so the next session (or the next machine
 
 > **Status 2026-08-14 17:00 — SUPERSEDED IN PART. The primary is live, exposed, and seeded.**
 > Serving since 2026-08-12 at `https://mempalace.jordbo.se/mcp`. Seeded 2026-08-14 15:07 from
-> EMB-7KJ4VR4G's palace — 14,777 drawers / 9 wings / 16,337 embeddings / KG 46 entities, 34 triples,
+> EMB-7KJ4VR4G's palace (itself a carry-over from the previous work computer EMB-X1JY06WJ — rfc-001 §4.4)
+> — 14,777 drawers / 9 wings / 16,337 embeddings / KG 46 entities, 34 triples,
 > now 14,803 drawers. One client (EMB-7KJ4VR4G's pi-devbox container) is flipped and verified
 > end-to-end. Both Phase 0 blockers below are cleared.
 >