asset-engine + irv-ml1: scaffold orchestrator wiring

Three changes prepping infra for asset_engine's orchestration feature
(SSH-driven bring-up / bring-down of irv-ml1 inference services with
per-device VRAM gating, contract in vh/asset-engine commit 5a36f8c):

1. asset-engine compose + .env.example + playbook gain a read-only
   bind-mount for /app/runtime/ssh — the dedicated ed25519 keypair
   (generated on ana-docker, not in the repo) plus a pinned known_hosts
   for irv-ml1's host fingerprint. Env vars SSH_KEY_PATH and
   SSH_KNOWN_HOSTS are exposed for the app to consume.

2. docs/asset-engine/services.yaml gains a `lifecycle: { stack, vram_gb,
   gpu_device_id }` block on each of 12 orchestratable irv-ml1 services
   (kokoro, chatterbox, index-tts, qwen3-tts, cosyvoice, fish-s2,
   kyutai-tts, vibevoice, voxtral, parakeet, stable-audio-open, ace-step).
   VRAM numbers are estimates from model footprint at fp16 — tune from
   real nvidia-smi measurements once the gate is live. comfyui and
   kokoro-captioned are deliberately excluded (variable-VRAM and
   shared-container respectively).

3. servers/irv-ml1/README.md docker-stacks table now lists all 13
   inference stacks (was only dockge + agents + comfyui) with port +
   GPU pinning columns.

Pubkey deployed to ~lkraven/.ssh/authorized_keys on irv-ml1;
end-to-end SSH from ana-docker → irv-ml1 verified with strict
host-key checking.

docs/asset-engine/services.yaml

@@ -28,6 +28,10 @@ services:
     category: tts
     version: 2
     host: irv-ml1
+    lifecycle:
+      stack: kokoro
+      vram_gb: 2
+      gpu_device_id: null
     endpoint: http://10.100.79.3:8193/v1/audio/speech
     method: POST
     content_type: application/json
@@ -201,6 +205,10 @@ services:
     version: 1
     status: down
     host: irv-ml1
+    lifecycle:
+      stack: chatterbox
+      vram_gb: 4
+      gpu_device_id: 0
     endpoint: http://10.100.79.3:8196/v1/audio/speech
     method: POST
     content_type: application/json
@@ -261,6 +269,10 @@ services:
     version: 1
     status: down
     host: irv-ml1
+    lifecycle:
+      stack: index-tts
+      vram_gb: 6
+      gpu_device_id: null
     endpoint: http://10.100.79.3:8192/v1/audio/speech
     method: POST
     content_type: application/json
@@ -337,6 +349,10 @@ services:
     version: 1
     status: down
     host: irv-ml1
+    lifecycle:
+      stack: qwen3-tts
+      vram_gb: 16
+      gpu_device_id: null
     endpoint: http://10.100.79.3:8191/v1/audio/speech
     method: POST
     content_type: application/json
@@ -394,6 +410,10 @@ services:
     version: 1
     status: down
     host: irv-ml1
+    lifecycle:
+      stack: cosyvoice
+      vram_gb: 4
+      gpu_device_id: null
     endpoint: http://10.100.79.3:8190/v1/audio/speech
     method: POST
     content_type: application/json
@@ -454,6 +474,10 @@ services:
     category: tts
     version: 1
     host: irv-ml1
+    lifecycle:
+      stack: fish-s2
+      vram_gb: 4
+      gpu_device_id: 1
     endpoint: http://10.100.79.3:8195/v1/tts
     method: POST
     content_type: application/json
@@ -503,6 +527,10 @@ services:
     version: 1
     status: down
     host: irv-ml1
+    lifecycle:
+      stack: kyutai-tts
+      vram_gb: 6
+      gpu_device_id: 0
     endpoint: http://10.100.79.3:8198/v1/audio/speech
     method: POST
     content_type: application/json
@@ -552,6 +580,10 @@ services:
     category: tts
     version: 2
     host: irv-ml1
+    lifecycle:
+      stack: vibevoice
+      vram_gb: 20
+      gpu_device_id: 1
     endpoint: http://10.100.79.3:8194/v1/audio/speech
     method: POST
     content_type: application/json
@@ -636,6 +668,10 @@ services:
     version: 1
     status: down
     host: irv-ml1
+    lifecycle:
+      stack: voxtral
+      vram_gb: 12
+      gpu_device_id: 1
     endpoint: http://10.100.79.3:8197/v1/audio/speech
     method: POST
     content_type: application/json
@@ -689,6 +725,10 @@ services:
     category: asr
     version: 1
     host: irv-ml1
+    lifecycle:
+      stack: parakeet
+      vram_gb: 2
+      gpu_device_id: null
     endpoint: http://10.100.79.3:8765/transcribe
     method: POST
     content_type: multipart/form-data
@@ -724,6 +764,10 @@ services:
     category: sfx
     version: 1
     host: irv-ml1
+    lifecycle:
+      stack: stable-audio-open
+      vram_gb: 6
+      gpu_device_id: 1
     endpoint: http://10.100.79.3:8211/v1/audio/sfx
     method: POST
     content_type: application/json
@@ -787,6 +831,10 @@ services:
     category: music
     version: 5
     host: irv-ml1
+    lifecycle:
+      stack: ace-step
+      vram_gb: 16
+      gpu_device_id: 1
     endpoint: http://10.100.79.3:8210/generate
     method: POST
     content_type: application/json