runbooks: log P5-13 media-server kernel upgrade to 6.8.0-134

Rebooted 2026-07-01; post-boot checks green (nvidia/DKMS, 54 containers,
18 Prom targets, 0 failed units, /mnt/media). Documents the gluetun
caveat: a stale PIA WG peer does not survive a reboot -> run
pia-wg/regen-and-up.sh as a required post-reboot step.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

runbooks/phase5-incident-log.md

@@ -307,6 +307,29 @@ Subscriber reminder: subscribe ntfy client to topic `health-digest` on 192.168.9
 
 ---
 
+### P5-13 — media-server Kernel Upgrade 6.8.0-124 → 6.8.0-134 (DONE 2026-07-01)
+
+**Host:** media-server (192.168.99.183 / VM 101)
+**Rebooted:** 2026-07-01 23:54 CDT into `6.8.0-134-generic` (was running `-124`).
+
+Kernel was staged earlier that day (6.8.0-134 on disk; `nvidia-srv/580.159.03` DKMS module built + signed for -134). `GRUB_DEFAULT=0` → reboot booted -134; `-124` and `-117` remain DKMS-built in the GRUB Advanced menu as fallbacks. Rollback strategy = PBS live backup of VM 101 (nvmebak storage can't snapshot without shutdown).
+
+**Post-boot checks — all green:**
+- `uname -r` = `6.8.0-134-generic`
+- `nvidia-smi` — both Quadro P2200s present, driver 580.159.03 loaded; `dkms status` shows nvidia-srv built for -134
+- 54/54 containers running, none restarting/unhealthy
+- 18/18 Prometheus targets up
+- 0 failed systemd units
+- `/mnt/media` (TrueNAS .29 NFS) mounted
+
+**⚠️ Gluetun caveat — a stale PIA WireGuard peer does NOT survive a host reboot.** After the reboot gluetun came back on the last-written `wg0.conf` (Jun-30 peer, endpoint `181.41.206.145`) which no longer passed traffic: tight VPN restart loop, healthchecks failing with `dial tcp4: lookup github.com/cloudflare.com: i/o timeout`, `public_ip` stuck at `""`. Even though that peer had been freshly registered Jun 30, it did not survive the cold start. Fixed by running the documented self-heal:
+```bash
+~/downloads/pia-wg/regen-and-up.sh    # regen fresh peer → recreate gluetun → reconnect sab/transmission
+```
+Result: fresh `us_denver` peer (endpoint `181.41.206.159:1337`), gluetun Healthy, egress verified as PIA Denver, Colorado. **Treat `regen-and-up.sh` as a required post-reboot step for the downloads stack — don't wait for the VpnTunnelDown alert.**
+
+---
+
 ## Known Config Drift (not incidents — track for cleanup)
 
 | Item | Location | Drift |