feat: AI face enhancement with GFPGAN and CodeFormer (#61)

* feat(shared): add enhance-faces tool definition and i18n strings

* feat(ai): add face enhancement script with GFPGAN and CodeFormer support

Detects faces via MediaPipe dual-model approach, then enhances using
GFPGAN (proven) or CodeFormer (via codeformer-pip) with auto fallback.
Supports strength-based alpha blending with original image.

* feat(ai): add TypeScript bridge for face enhancement

* feat(api): add enhance-faces route with GFPGAN/CodeFormer support

* feat(web): add enhance-faces settings component and register in tool registry

* feat(docker): add CodeFormer dependency and model download

- Add codeformer-pip to both CPU and GPU requirements
- Download CodeFormer model (~375MB) at Docker build time
- Add CodeFormer to smoke test verification

* fix(enhance-faces): address code review findings

- Skip alpha blend for CodeFormer (strength already applied via fidelity weight)
- Hide "only enhance main face" checkbox when Best (CodeFormer) is selected
- Fix sensitivity slider labels (swap More/Fewer faces to match actual behavior)
- Register EnhanceFacesControls in pipeline step settings
- Remove model names from user-facing descriptions

* fix(enhance-faces): fix CodeFormer integration and Docker setup

- Add codeformer-pip install to Dockerfile with --no-deps to avoid numpy 2.x conflict
- Re-pin numpy==1.26.4 after codeformer-pip install
- Pin codeformer-pip==0.0.4 in requirements files
- Broaden auto-mode fallback to catch any Exception from CodeFormer

---------

Co-authored-by: stirling-image <stirling-image@users.noreply.github.com>

apps/web/src/components/tools/pipeline-step-settings.tsx

@@ -4,6 +4,7 @@ import { ColorControls } from "./color-settings";
 import { CompressControls } from "./compress-settings";
 import { ConvertControls } from "./convert-settings";
 import { CropControls } from "./crop-settings";
+import { EnhanceFacesControls } from "./enhance-faces-settings";
 import { GifToolsControls } from "./gif-tools-settings";
 import { NoiseRemovalControls } from "./noise-removal-settings";
 import { RemoveBgControls } from "./remove-bg-settings";
@@ -43,6 +44,8 @@ export function PipelineStepSettings({ toolId, settings, onChange }: PipelineSte
   if (toolId === "gif-tools") return <GifToolsControls settings={settings} onChange={onChange} />;
   if (toolId === "upscale") return <UpscaleControls settings={settings} onChange={onChange} />;
   if (toolId === "blur-faces") return <BlurFacesControls settings={settings} onChange={onChange} />;
+  if (toolId === "enhance-faces")
+    return <EnhanceFacesControls settings={settings} onChange={onChange} />;
   if (toolId === "remove-background")
     return <RemoveBgControls settings={settings} onChange={onChange} />;
   if (toolId === "noise-removal")