Read engine configuration live instead of asserting it in the dashboard

The engine subtitles were hardcoded: "FlashAttention + Q4 KV Cache" and "DynamicVRAM
+ Pinned Async Offload". The first turned out to be accurate -- OLLAMA_FLASH_ATTENTION
and OLLAMA_KV_CACHE_TYPE really are set -- which is worse than being wrong, because it
would have gone on looking accurate after the settings changed.

engines.py reads both engines' real configuration: the ollama service environment via
systemd, and ComfyUI's own /system_stats for version, allocator, VRAM mode and argv.
Exposed at GET /api/engines, as an MCP tool, and in the dashboard subtitles with the
full settings list as a tooltip.

The settings worth surfacing are the ones that dictate how this service must behave
and that previously had to be discovered by reading journald: OLLAMA_NUM_PARALLEL=1
is why an unload queues behind a running generation and is reported as deferred
rather than failed, and OLLAMA_MAX_LOADED_MODELS=1 is why every swap evicts the
previous model. Each is reported with that explanation attached.

Writing the tests found a bug in the new code: (system.get("python_version") or
"").split()[0] raises IndexError when ComfyUI omits the field, and the surrounding
except would have swallowed it and reported ComfyUI as entirely offline.

Tests: 192 (was 182).

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

static/index.html

@@ -194,7 +194,7 @@
               </div>
               <div>
                 <h3 class="font-bold text-slate-100 text-sm">Ollama LLM Engine</h3>
-                <p class="text-xs text-slate-400">Port :11434 // FlashAttention + Q4 KV Cache</p>
+                <p class="text-xs text-slate-400" id="ollama-engine-sub" title="Read live from the ollama service environment">Port :11434</p>
               </div>
             </div>
             <button onclick="freeOllamaVRAM()" class="px-2.5 py-1 text-xs font-semibold rounded-lg bg-rose-950/70 border border-rose-800 text-rose-300 hover:bg-rose-900 transition flex items-center space-x-1">
@@ -265,7 +265,7 @@
               </div>
               <div>
                 <h3 class="font-bold text-slate-100 text-sm">ComfyUI Diffusion Engine</h3>
-                <p class="text-xs text-slate-400">Port :8188 // DynamicVRAM + Pinned Async Offload</p>
+                <p class="text-xs text-slate-400" id="comfy-engine-sub" title="Read live from ComfyUI's /system_stats">Port :8188</p>
               </div>
             </div>
             <button onclick="freeComfyVRAM()" class="px-2.5 py-1 text-xs font-semibold rounded-lg bg-rose-950/70 border border-rose-800 text-rose-300 hover:bg-rose-900 transition flex items-center space-x-1">