PR #804 added pciutils to the admin image so AMD detection could fall
back to lspci. Side effect for NVIDIA: si.graphics() now finds the card
via lspci but reads the BAR0 region size (16-32 MiB on most NVIDIA
cards) as VRAM, since nvidia-smi isn't installed in the admin image to
enrich the result. A GTX 1050 Ti showed 32 MB instead of 4096.
The nvidia-smi-via-Ollama and Ollama log probes already give the right
number, but they only ran when graphics.controllers came back empty.
Extend the trigger so they also run when the only entries are NVIDIA
controllers reporting under 256 MiB (no real dGPU has that little). If
the probes can't reach a value either (Ollama not installed, passthrough
broken), VRAM now falls back to N/A instead of the bogus 32.
Verified locally on an RTX 4070 Ti by simulating the container condition
(lspci available, nvidia-smi unreachable). Before the fix: vram 32, model
"AD104 [GeForce RTX 4070 Ti]". After: vram 12288, model "NVIDIA GeForce
RTX 4070 Ti", from the Ollama inference-compute log line. Also confirmed
the same result inside the actual admin Docker image.