Fix publish_release.sh to upload installer + AppImage; document host REQUIRE_SIGNIN_VIEW

- Script uploaded only the three portable binaries; v0.2.1 release was
  missing step-line-setup-0.2.1.exe and the AppImage. Now uploads the full
  set (extras when present), reuses existing releases (adds missing assets),
  and falls back to ~/.git-credentials basic auth when GITEA_TOKEN is unset
- Back-filled both missing assets onto the live v0.2.1 release via API
  (release now carries all 5 artifacts)
- TODO/RELEASING/MEMORY document the findings and the host admin steps for
  anonymous downloads ([service] REQUIRE_SIGNIN_VIEW)

tools/generate_textures.py

@@ -316,8 +316,10 @@ def app_icon():
     src_png = os.path.join(ASSETS, "icon.png")
     ran = False
     for cmd in (
-        ["magick", src_png, "-background", "none", "-define", "icon:auto-resize=48,32,16", ico_path],
-        ["convert", src_png, "-background", "none", "-define", "icon:auto-resize=48,32,16", ico_path],
+        ["magick", src_png, "-background", "none", "-define",
+            "icon:auto-resize=48,32,16", ico_path],
+        ["convert", src_png, "-background", "none",
+            "-define", "icon:auto-resize=48,32,16", ico_path],
     ):
         try:
             subprocess.run(cmd, check=True, capture_output=True)
@@ -329,7 +331,8 @@ def app_icon():
         print("wrote assets/textures/icon.ico (BMP 16/32/48 via ImageMagick)")
     else:
         print("WARNING: ImageMagick not found; writing PIL ICO (may be PNG-compressed)")
-        Image.open(src_png).convert("RGBA").save(ico_path, format="ICO", sizes=[(48, 48), (32, 32), (16, 16)])
+        Image.open(src_png).convert("RGBA").save(
+            ico_path, format="ICO", sizes=[(48, 48), (32, 32), (16, 16)])
 
 
 def cards():
@@ -369,8 +372,8 @@ def _api_key() -> str:
     return key
 
 
-def _generate_image(prompt: str, model: str, size: int,
-                    transparent: bool = False) -> Image.Image:
+def generate_image(prompt: str, model: str, size: int,
+                   transparent: bool = False) -> Image.Image:
     """Call the OpenRouter image API and return the decoded PIL image.
 
     Requests a square image at `size` px and decodes the base64 PNG/JPEG/WebP
@@ -435,7 +438,7 @@ def _fit(img: Image.Image, max_dim: int = MAX_DIM) -> Image.Image:
 def generate_ai_textures(prompt: str, name: str, model: str, size: int,
                          transparent: bool = False) -> None:
     """Generate one texture via OpenRouter and save it under assets/textures/."""
-    img = _generate_image(prompt, model, size, transparent)
+    img = generate_image(prompt, model, size, transparent)
     img = _fit(img)
     if transparent:
         img = img.convert("RGBA")