feat(model-manager): generated-photo Gallery + device-routing landing

- Gallery view: grid of generated photos from ComfyUI's output/, full-size
  lightbox, and permanent delete (with confirm). Paginated ("Load more").
- Backend: GET /api/gallery, GET /gallery/file (path-guarded image serve),
  DELETE /api/gallery (path-guarded; clear error on permission denial).
- Mount ./output read-write into model-manager so the gallery can delete.
- Device-routing landing at /start: phones -> ComfyUIMini, desktops ->
  the Gallery; ?force=mobile|desktop overrides. Ports come from the new
  /api/ui-config (COMFYUI_PORT / COMFYUIMINI_PORT env).
- Responsive tweaks so the gallery is usable if opened directly on a phone.

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

model-manager/app/main.py

@@ -13,11 +13,16 @@ from pydantic import BaseModel
 
 from . import db, downloader, registries
 from .config import (
+    COMFYUI_PORT,
+    COMFYUIMINI_PORT,
+    IMAGE_EXTS,
     KEY_BY_FOLDER,
     MODEL_TYPES,
     MODELS_DIR,
+    OUTPUT_DIR,
     TYPE_BY_KEY,
     ensure_dirs,
+    safe_output_path,
 )
 
 STATIC_DIR = Path(__file__).parent / "static"
@@ -214,6 +219,78 @@ def delete_download(download_id: int) -> dict:
     return {"removed": download_id}
 
 
+# ---- gallery (generated photos) -------------------------------------------
+
+@app.get("/api/gallery")
+def list_gallery(limit: int = 60, offset: int = 0) -> dict:
+    """List generated images under OUTPUT_DIR, newest first, paginated."""
+    files: list[dict] = []
+    if OUTPUT_DIR.is_dir():
+        for path in OUTPUT_DIR.rglob("*"):
+            if not path.is_file() or path.suffix.lower() not in IMAGE_EXTS:
+                continue
+            rel = path.relative_to(OUTPUT_DIR).as_posix()
+            stat = path.stat()
+            files.append({
+                "path": rel,
+                "name": path.name,
+                "subfolder": path.parent.relative_to(OUTPUT_DIR).as_posix()
+                if path.parent != OUTPUT_DIR else "",
+                "size": stat.st_size,
+                "mtime": stat.st_mtime,
+            })
+    files.sort(key=lambda f: f["mtime"], reverse=True)
+    total = len(files)
+    page = files[offset:offset + max(1, min(limit, 500))]
+    return {"items": page, "total": total,
+            "offset": offset, "returned": len(page)}
+
+
+@app.get("/gallery/file")
+def gallery_file(path: str):
+    try:
+        target = safe_output_path(path)
+    except ValueError:
+        raise HTTPException(400, "Invalid path")
+    if not target.is_file() or target.suffix.lower() not in IMAGE_EXTS:
+        raise HTTPException(404, "Image not found")
+    return FileResponse(target)
+
+
+class DeletePhotoIn(BaseModel):
+    path: str
+
+
+@app.delete("/api/gallery")
+def delete_photo(body: DeletePhotoIn) -> dict:
+    try:
+        target = safe_output_path(body.path)
+    except ValueError:
+        raise HTTPException(400, "Invalid path")
+    if not target.is_file():
+        raise HTTPException(404, "Image not found")
+    try:
+        target.unlink()
+    except PermissionError:
+        raise HTTPException(
+            403,
+            "Permission denied (file is in a folder owned by another user). "
+            "Run ComfyUI as the same UID, or remove it from a host shell.")
+    return {"deleted": body.path}
+
+
+# ---- device routing / ui config -------------------------------------------
+
+@app.get("/api/ui-config")
+def ui_config() -> dict:
+    return {"comfyui_port": COMFYUI_PORT, "comfyuimini_port": COMFYUIMINI_PORT}
+
+
+@app.get("/start")
+def start() -> FileResponse:
+    return FileResponse(STATIC_DIR / "start.html")
+
+
 # ---- static UI ------------------------------------------------------------
 
 @app.get("/")