docs(sd): mark SD-on-SPI3 verified on hardware

Re-ran the spike on the dedicated SPI3 wiring (CLK 14 / MOSI 15) with
the same clean mount + atomic round-trip result. Flip the docs from
"pending a re-run" to verified.

docs/hardware.md

@@ -30,5 +30,5 @@ live in [`spikes.md`](spikes.md) and
 [`v0.1-mvp-technical.md`](v0.1-mvp-technical.md#hardware-bring-up-order),
 with failure write-ups in [`postmortems/`](postmortems/README.md). Notable: the
 keyboard runs bus-powered on the S3's native USB port, and the SD/FAT stack is
-verified on a 32 GB card (2026-07-11), now moving to its own SPI3 host per
-ADR-012 ([postmortem](postmortems/2026-07-05-spike3-sd-cmd59.md)).
+verified on a 32 GB card on its own SPI3 host (2026-07-11, ADR-012)
+([postmortem](postmortems/2026-07-05-spike3-sd-cmd59.md)).

docs/postmortems/2026-07-05-spike3-sd-cmd59.md

@@ -191,8 +191,8 @@ it is explicitly **not recommended** and not applied.
 - [x] Enable PSRAM (done, `CONFIG_SPIRAM`) and build Spike 7 (git push) — both
       complete; see [Spike 7 postmortem](2026-07-05-spike7-gix-https-push.md).
 - [x] Settle the **shared-bus arbitration** decision → **SD on its own SPI3**
-      (ADR-012, 2026-07-11); spike rewired to SPI3 (SCK 14 / MOSI 15), pending a
-      bench re-run on the new wiring.
+      (ADR-012, 2026-07-11); spike rewired to SPI3 (SCK 14 / MOSI 15) and
+      **re-verified on hardware 2026-07-11** — same mount + round-trip result.
 - [ ] **Still open:** implement the FatFS atomic-save (unlink-then-rename +
       `*.tmp` boot-recovery) in the real `persistence` module.