feat: SOTA image enhancement with one-click auto-improve (#55)

* feat(image-enhancement): add analysis and correction types

* feat(image-enhancement): implement auto-enhance analysis and correction engine

* test(image-enhancement): add unit tests for auto-enhance engine

* feat(image-enhancement): add API route with analyze endpoint and register in constants/i18n

* feat(image-enhancement): add UI component with mode selector, intensity slider, and analysis badges

* test(image-enhancement): add integration and e2e tests

* fix(image-enhancement): use modulate instead of gamma for exposure correction

Sharp's gamma() only accepts values between 1.0 and 3.0, but brightening
underexposed images computed gamma < 1.0. Switch to modulate({ brightness })
which handles both brightening and darkening correctly.

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

apps/api/src/routes/tools/index.ts

@@ -20,6 +20,7 @@ import { registerEraseObject } from "./erase-object.js";
 import { registerFavicon } from "./favicon.js";
 import { registerFindDuplicates } from "./find-duplicates.js";
 import { registerGifTools } from "./gif-tools.js";
+import { registerImageEnhancement } from "./image-enhancement.js";
 import { registerImageToPdf } from "./image-to-pdf.js";
 import { registerInfo } from "./info.js";
 import { registerOcr } from "./ocr.js";
@@ -125,6 +126,7 @@ export async function registerToolRoutes(app: FastifyInstance): Promise<void> {
     { id: "blur-faces", register: registerBlurFaces },
     { id: "erase-object", register: registerEraseObject },
     { id: "smart-crop", register: registerSmartCrop },
+    { id: "image-enhancement", register: registerImageEnhancement },
     { id: "content-aware-resize", register: registerContentAwareResize },
   ];