Use tmux for test runner — detachable SSH sessions

Tests now run inside a tmux session so you can disconnect and
reconnect without interrupting multi-hour test runs.

Changes:
- create-vm.sh: cloud-init no longer auto-runs tests, just provisions
  packages and clones the repo. Installs a `darkforge-test` command
  in /usr/local/bin that wraps run-in-vm.sh in tmux.
- run-in-vm.sh: detects when called as `darkforge-test` and re-execs
  inside a tmux session named "darkforge". --tmux flag for internal use.
- README updated with tmux workflow (detach/reattach instructions).

Workflow:
  ssh darkforge@<ip>
  darkforge-test --quick    # starts in tmux
  Ctrl+B D                  # detach, go do other things
  tmux attach -t darkforge  # come back later

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

tests/proxmox/README.md

@@ -40,33 +40,63 @@ Without the target hardware (9950X3D / RTX 5090), we can still test:
 ### 1. Create the test VM (run on Proxmox host)
 
 ```bash
-# Copy scripts to Proxmox host
-scp tests/proxmox/create-vm.sh root@proxmox:/root/
-scp tests/proxmox/run-in-vm.sh root@proxmox:/root/
-
-# Create the VM
-ssh root@proxmox bash /root/create-vm.sh
+# Copy the script to Proxmox and run it
+scp tests/proxmox/create-vm.sh root@your-proxmox:/root/
+ssh root@your-proxmox bash /root/create-vm.sh
 ```
 
-### 2. Run the tests (automated via cloud-init or manual SSH)
+This creates the VM and cloud-init installs all packages + clones the repo. Wait ~5 minutes for provisioning to complete.
+
+### 2. SSH in and run tests
 
 ```bash
-# Option A: wait for cloud-init to finish (fully automated)
-# The VM runs tests automatically on first boot.
+# Get the VM IP from Proxmox
+ssh root@your-proxmox "qm guest cmd 900 network-get-interfaces" | grep ip-address
 
-# Option B: SSH in and run manually
-ssh darkforge@<vm-ip> bash /home/darkforge/run-in-vm.sh
+# SSH into the VM
+ssh darkforge@<VM_IP>    # password: darkforge
 ```
 
+Then start the tests. They run inside a **tmux session** so you can disconnect and reconnect without interrupting them:
+
+```bash
+# Full test suite (~2-6 hours) — runs in tmux, safe to disconnect
+darkforge-test
+
+# Fast mode (~30 min) — skips toolchain/kernel/ISO builds
+darkforge-test --quick
+
+# Medium mode (~1 hour) — skips only toolchain bootstrap
+darkforge-test --no-build
+```
+
+**tmux controls:**
+- `Ctrl+B` then `D` — detach (tests keep running in background)
+- `tmux attach -t darkforge` — reattach to see progress
+- `tmux ls` — list running sessions
+
 ### 3. Collect the report
 
+Once tests finish (check with `tmux attach -t darkforge`):
+
 ```bash
-scp darkforge@<vm-ip>:/home/darkforge/darkforge/tests/report.json ./
-scp darkforge@<vm-ip>:/home/darkforge/darkforge/tests/report.txt ./
+# From your local machine
+scp darkforge@<VM_IP>:~/darkforge/tests/report.json ./
+scp darkforge@<VM_IP>:~/darkforge/tests/report.txt ./
+```
+
+The `report.txt` is a human-readable summary. The `report.json` is machine-readable and can be given to the development process for automated debugging.
+
+### 4. Re-run after code changes
+
+```bash
+ssh darkforge@<VM_IP>
+cd ~/darkforge
+git pull --recurse-submodules
+darkforge-test --quick    # re-run tests
 ```
 
 ## Files
 
 - `create-vm.sh` — runs on the Proxmox host, creates and configures the VM
-- `run-in-vm.sh` — runs inside the VM, clones the project and runs all tests
-- `cloud-init-user.yaml` — cloud-init user-data for automated first-boot testing
+- `run-in-vm.sh` — runs inside the VM, executes all test suites, generates reports