Point PCAN rebuild steps at ~/infra instead of /tmp

The driver source sat in /tmp and was gone after a reboot, leaving the
"after a kernel update" steps unusable. Re-fetched PEAK 9.2.0 into
~/infra/peak-linux-driver-9.2.0 per GUIDELINES §1; it is the same
release as the installed pcan.ko (Release_20260707_n).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

docs/impl/reports/PCAN-SETUP.md

@@ -138,6 +138,9 @@ sudo candump can1
 
 Source files left at `/tmp/peak-linux-driver-9.2.0/` and `/tmp/pcan-driver.tar.gz`. Can be removed after verifying everything works.
 
+> **2026-10-08:** `/tmp` copies are gone (cleared on reboot). Source now kept at `~/infra/peak-linux-driver-9.2.0/`
+> (fetched from `https://www.peak-system.com/fileadmin/media/linux/files/peak-linux-driver-9.2.0.tar.gz`).
+
 ## Current Status — 2026-08-05
 
 This report was written during an earlier session. On this machine (hostname: `mikkeli-orin-nano`,
@@ -174,10 +177,12 @@ sudo candump canX
 
 ### After a kernel update
 
-This is an out-of-tree module. Rebuild with:
+This is an out-of-tree module. The source was lost from `/tmp` on reboot and re-fetched on 2026-10-08 into
+`~/infra/peak-linux-driver-9.2.0/` (per [GUIDELINES §1](../../GUIDELINES.md)). It is the same release as the installed module,
+`Release_20260707_n`. Rebuild with:
 
 ```bash
-cd /tmp/peak-linux-driver-9.2.0/driver
+cd ~/infra/peak-linux-driver-9.2.0/driver
 make clean
 make NET=NETDEV_SUPPORT all
 sudo cp pcan.ko /lib/modules/$(uname -r)/misc/pcan.ko