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/create-vm.sh

@@ -144,6 +144,7 @@ packages:
   - bc
   - rsync
   - openssh
+  - tmux
 
 runcmd:
   # Grow the partition to fill the disk
@@ -159,21 +160,26 @@ runcmd:
         echo "CLONE FAILED — manually clone the repo"
     '
 
-  # Copy the test runner
+  # Create the darkforge-test convenience command
   - |
-    if [ -f /home/darkforge/darkforge/tests/proxmox/run-in-vm.sh ]; then
-      cp /home/darkforge/darkforge/tests/proxmox/run-in-vm.sh /home/darkforge/
-      chown darkforge:darkforge /home/darkforge/run-in-vm.sh
-      chmod +x /home/darkforge/run-in-vm.sh
+    cat > /usr/local/bin/darkforge-test << 'DTEOF'
+    #!/bin/bash
+    SCRIPT="/home/darkforge/darkforge/tests/proxmox/run-in-vm.sh"
+    if [ ! -f "$SCRIPT" ]; then
+      echo "ERROR: Test script not found. Is the repo cloned?"
+      echo "  git clone --recurse-submodules https://git.dannyhaslund.dk/danny8632/darkforge.git ~/darkforge"
+      exit 1
     fi
+    ARGS="$*"
+    exec tmux new-session -d -s darkforge \
+      "bash ${SCRIPT} --tmux ${ARGS}; echo ''; echo 'Tests finished. Press Enter to close.'; read" \; \
+      attach-session -t darkforge
+    DTEOF
+    chmod +x /usr/local/bin/darkforge-test
 
-  # Run the test suite automatically
-  - |
-    su - darkforge -c '
-      if [ -f /home/darkforge/run-in-vm.sh ]; then
-        bash /home/darkforge/run-in-vm.sh 2>&1 | tee /home/darkforge/test-output.log
-      fi
-    '
+  # Signal that provisioning is done
+  - touch /home/darkforge/.provisioned
+  - chown darkforge:darkforge /home/darkforge/.provisioned
 CLOUDINIT
 
 qm set "${VMID}" --cicustom "user=local:snippets/darkforge-test-init.yaml"
@@ -187,23 +193,22 @@ echo ""
 echo "═══════════════════════════════════════════════"
 echo " VM ${VMID} created and starting."
 echo ""
-echo " The VM will:"
-echo "   1. Boot Arch Linux"
-echo "   2. Install required packages via cloud-init"
-echo "   3. Clone the DarkForge repository"
-echo "   4. Run the full test suite"
+echo " Cloud-init will install packages and clone the repo."
+echo " Wait ~5 min for provisioning, then SSH in to run tests."
 echo ""
-echo " Monitor progress:"
-echo "   qm terminal ${VMID}     (serial console)"
+echo " Get the VM IP:"
+echo "   qm guest cmd ${VMID} network-get-interfaces | grep -oP '\"ip-address\":\\s*\"\\K[0-9.]+'"
 echo ""
-echo " SSH access (after boot):"
-echo "   ssh darkforge@\$(qm guest cmd ${VMID} network-get-interfaces | grep -oP '\"ip-address\":\\s*\"\\K[0-9.]+')"
-echo "   Password: darkforge"
+echo " SSH in:"
+echo "   ssh darkforge@<IP>        (password: darkforge)"
 echo ""
-echo " Or get IP:"
-echo "   qm guest cmd ${VMID} network-get-interfaces"
+echo " Run tests in a tmux session (detachable):"
+echo "   darkforge-test             # starts tests in tmux"
+echo "   darkforge-test --quick     # fast mode (30 min)"
 echo ""
-echo " Collect report after tests finish:"
-echo "   VM_IP=\$(qm guest cmd ${VMID} network-get-interfaces | grep -oP '\"ip-address\":\\s*\"\\K[0-9.]+')"
-echo "   scp darkforge@\$VM_IP:/home/darkforge/darkforge/tests/report.* ./"
+echo " Detach from tmux:  Ctrl+B then D"
+echo " Reattach later:    tmux attach -t darkforge"
+echo ""
+echo " Collect report:"
+echo "   scp darkforge@<IP>:~/darkforge/tests/report.* ./"
 echo "═══════════════════════════════════════════════"