Fix pony repo and surface daemon swap failures (Arc integration)

Integration on the real Arc B580 uncovered two issues:

- The pony repo AstraliteHeart/pony-diffusion-v6-xl is gated (HF returns
  401 Repository Not Found), so swaps to it failed. Point the pony key at
  kitty7779/ponyDiffusionV6XL, an ungated diffusers-format mirror with
  safetensors weights that loads cleanly via the existing fp16 fallback.
- The wrapper swallowed a failed model swap: under set -e the unguarded
  swap curl aborted the script with exit 0 and no message. Capture the
  /model response and HTTP status, print the daemon's error, and exit 1
  when the swap does not return 200.

sdxl, realvis, and pony all verified end to end (one-shot + daemon),
output owned by the host user, peak within the 12GB budget.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

2 files changed, 11 insertions, 3 deletions

diff --git a/generate.py b/generate.py
index 9cbc167..95b2dd7 100644
--- a/generate.py
+++ b/generate.py
@@ -27,7 +27,7 @@ from diffusers import StableDiffusionXLPipeline, AutoencoderKL
 MODELS = {
     "sdxl":    "stabilityai/stable-diffusion-xl-base-1.0",  # default, general
     "realvis": "SG161222/RealVisXL_V5.0",                   # photoreal, permissive
-    "pony":    "AstraliteHeart/pony-diffusion-v6-xl",       # unrestricted, versatile
+    "pony":    "kitty7779/ponyDiffusionV6XL",               # unrestricted, versatile (ungated diffusers-format mirror)
 }
 DEFAULT_MODEL = "sdxl"
 # fp16-fix VAE avoids the fp32 upcast that OOMs a 12GB card at decode time.
diff --git a/imggen b/imggen
index 749f64a..c5689d4 100755
--- a/imggen
+++ b/imggen
@@ -95,8 +95,16 @@ if daemon_up; then
     current="$(curl -s "${BASE}/status" | sed -n 's/.*"model": *"\([^"]*\)".*/\1/p')"
     if [ "$current" != "$MODEL" ]; then
         echo "swapping daemon model $current -> $MODEL ..." >&2
-        curl -sf -X POST "${BASE}/model" -H 'Content-Type: application/json' \
-            -d "{\"name\":\"$MODEL\"}" >/dev/null
+        # Capture body and status; a failed swap (bad/gated repo, OOM) must be
+        # surfaced, not silently swallowed by set -e killing the script.
+        swap_body="$(curl -s -w '\n%{http_code}' -X POST "${BASE}/model" \
+            -H 'Content-Type: application/json' -d "{\"name\":\"$MODEL\"}")"
+        swap_code="${swap_body##*$'\n'}"
+        swap_msg="${swap_body%$'\n'*}"
+        if [ "$swap_code" != "200" ]; then
+            echo "swap to '$MODEL' failed (HTTP $swap_code): $swap_msg" >&2
+            exit 1
+        fi
     fi
 
     # Build JSON request. jq not assumed; hand-build (values are ours/simple).