fix: remove serial console (root cause of 30s boot delay), enable syslog logging, disk auto-detect

Root cause found: console=ttyS0,115200n8 causes 30-second timeout at every
systemd boot phase on hardware without a physical serial UART. Each phase
transition blocks waiting for the non-existent UART.

Changes:
- Remove console=ttyS0 from kickstart bootloader args and %post setup
- Enable Anaconda syslog forwarding (logging --host --port) for install visibility
- Improve syslog IP→MAC resolution (register from kickstart fetch + progress)
- Fix disk auto-detect: default to empty string (not /dev/sda) for NVMe support
- Enable SysRq magic keys (kernel.sysrq=1) for emergency reboot via JetKVM
- Simplify debug command: remove --sshd flag (inst.sshd always available),
  add /debug-setup.sh HTTP endpoint for nc listener setup
- Add labctl provision logs -f (follow mode with polling)
- Add syslog listener unit tests
- Enable syslog log capture test in integration suite

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

bastion/src/labd/src/routes/bastions.ts

@@ -151,7 +151,7 @@ export function registerBastionRoutes(app: FastifyInstance, db: DbClient): void
         try {
           const result = await sendCommand(all[0]!.bastionId, {
             type: "command-install",
-            mac, hostname, disk: disk ?? "/dev/sda", role: role ?? "infra", os: os ?? "fedora-43",
+            mac, hostname, disk: disk ?? "", role: role ?? "infra", os: os ?? "fedora-43",
           });
           return reply.code(result.status === "ok" ? 200 : 500).send(result);
         } catch (err) {
@@ -164,7 +164,7 @@ export function registerBastionRoutes(app: FastifyInstance, db: DbClient): void
     try {
       const result = await sendCommand(bastion.bastionId, {
         type: "command-install",
-        mac, hostname, disk: disk ?? "/dev/sda", role: role ?? "infra", os: os ?? "fedora-43",
+        mac, hostname, disk: disk ?? "", role: role ?? "infra", os: os ?? "fedora-43",
       });
       return reply.code(result.status === "ok" ? 200 : 500).send(result);
     } catch (err) {
@@ -174,10 +174,9 @@ export function registerBastionRoutes(app: FastifyInstance, db: DbClient): void
 
   // Queue debug/rescue mode — route to correct bastion by MAC
   app.post<{
-    Body: { mac?: string; sshd?: boolean; pxeBoot?: boolean };
+    Body: { mac?: string; pxeBoot?: boolean };
   }>("/api/machines/debug", async (request, reply) => {
     const mac = (request.body?.mac ?? "").toLowerCase().replace(/-/g, ":");
-    const sshd = request.body?.sshd ?? false;
     const pxeBoot = request.body?.pxeBoot ?? false;
     if (!mac) {
       return reply.code(400).send({ error: "mac is required" });
@@ -191,7 +190,7 @@ export function registerBastionRoutes(app: FastifyInstance, db: DbClient): void
       }
       if (all.length === 1) {
         try {
-          const result = await sendCommand(all[0]!.bastionId, { type: "command-debug", mac, sshd, pxeBoot });
+          const result = await sendCommand(all[0]!.bastionId, { type: "command-debug", mac, pxeBoot });
           return reply.code(result.status === "ok" ? 200 : 500).send(result);
         } catch (err) {
           return reply.code(500).send({ error: err instanceof Error ? err.message : String(err) });
@@ -201,7 +200,7 @@ export function registerBastionRoutes(app: FastifyInstance, db: DbClient): void
     }
 
     try {
-      const result = await sendCommand(bastion.bastionId, { type: "command-debug", mac, sshd, pxeBoot });
+      const result = await sendCommand(bastion.bastionId, { type: "command-debug", mac, pxeBoot });
       return reply.code(result.status === "ok" ? 200 : 500).send(result);
     } catch (err) {
       return reply.code(500).send({ error: err instanceof Error ? err.message : String(err) });