A served model can be moved to more cards, or fewer

llmgw ctl model gpus MODEL N [--profile P] [--in-place],
POST /api/v1/models/{name}/gpus and the console's GPUs…: how many cards of
one node each replica uses. Tensor parallel for vLLM, SGLang and
TensorRT-LLM, held to the model's KV heads (modelplan.SplitsHeads, now one
rule for the planner and this); the layers split for llama.cpp, its old
--tensor-split dropped. Refused for a count no node has, for cards that
would not hold the weights and the context, and for engines on one card.
The replicas start again beside the old ones; with no room beside them the
command says so, and --in-place stops each first.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

CHANGELOG.md

@@ -25,6 +25,20 @@ is only released once its **exit criterion** is met, not when its code lands.
 Until v1.0.0 the minor version is the breaking one: configuration formats and Go
 APIs change between minors without a deprecation period.
 
+## Unreleased
+
+### Added
+
+- **A served model moved to more cards, or fewer.** `llmgw ctl model gpus
+  MODEL N [--profile P] [--in-place]`, `POST /api/v1/models/{name}/gpus`, and
+  GPUs… in the console's model menu. How many cards of one node each replica
+  uses: tensor parallel for vLLM, SGLang and TensorRT-LLM, checked against
+  the model's KV heads, and the layers split for llama.cpp. Refused for a
+  count no node has, or whose cards would not hold the model and its
+  context, with the figures; its replicas are then started again on it, one
+  by one, beside the old — or, with `--in-place` when there is no room
+  beside them, each stopped first.
+
 ## v0.15.1 — 2026-10-29
 
 A 125B model on one card, a second mirror, and weights that run code