fix: resolve 5 bugs found during comprehensive tool testing

1. split batch 404: register split tool in batch registry via
   registerToolProcessFn() so /api/v1/tools/split/batch works

2. CodeFormer crash: inference_app() expects a file path, not a numpy
   array. Save to temp file before calling, read result back.

3. OCR fallback chain: fix case-sensitive "Segmentation fault" match
   that prevented PaddleOCR crash from triggering Tesseract fallback.
   Also add "process crashed" check. Upgrade ARM paddlepaddle to >=3.2.1.

4. blur-faces large images: downscale to 1920px max before MediaPipe
   detection, scale coordinates back. Also add rotation retry for
   portrait-oriented images where BlazeFace misses faces. Applied to
   detect_faces.py, enhance_faces.py, and restore.py.

5. color-adjustments tool ID: fix mismatch in index.ts registration
   array (was "color-adjustments", should be "adjust-colors").

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

@@ -92,7 +92,7 @@ export async function registerToolRoutes(app: FastifyInstance): Promise<void> {
     { id: "compress", register: registerCompress },
     { id: "strip-metadata", register: registerStripMetadata },
     { id: "edit-metadata", register: registerEditMetadata },
-    { id: "color-adjustments", register: registerColorAdjustments },
+    { id: "adjust-colors", register: registerColorAdjustments },
     { id: "sharpening", register: registerSharpening },
 
     // Watermark & Overlay

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

@@ -165,12 +165,13 @@ export function registerOcr(app: FastifyInstance) {
           });
         } catch (err) {
           lastError = err;
-          const msg = err instanceof Error ? err.message : String(err);
+          const msg = (err instanceof Error ? err.message : String(err)).toLowerCase();
           // If the Python process crashed (segfault, dispatcher exit), try next tier
           if (
             msg.includes("exited unexpectedly") ||
             msg.includes("exited with code") ||
-            msg.includes("Segmentation fault")
+            msg.includes("segmentation fault") ||
+            msg.includes("process crashed")
           ) {
             request.log.warn(
               { toolId: "ocr", quality: tier, err },

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

@@ -7,6 +7,7 @@ import { z } from "zod";
 import { autoOrient } from "../../lib/auto-orient.js";
 import { formatZodErrors } from "../../lib/errors.js";
 import { ensureSharpCompat } from "../../lib/heic-converter.js";
+import { registerToolProcessFn } from "../tool-factory.js";
 
 const settingsSchema = z.object({
   columns: z.number().min(1).max(100).default(3),
@@ -159,4 +160,87 @@ export function registerSplit(app: FastifyInstance) {
       }
     }
   });
+
+  registerToolProcessFn({
+    toolId: "split",
+    settingsSchema,
+    process: async (inputBuffer, _settings, filename) => {
+      const settings = _settings as z.infer<typeof settingsSchema>;
+      const metadata = await sharp(inputBuffer).metadata();
+      const fullW = metadata.width ?? 0;
+      const fullH = metadata.height ?? 0;
+
+      let cols = settings.columns;
+      let rows = settings.rows;
+      if (settings.tileWidth && settings.tileHeight) {
+        cols = Math.max(1, Math.ceil(fullW / settings.tileWidth));
+        rows = Math.max(1, Math.ceil(fullH / settings.tileHeight));
+      }
+      cols = Math.min(cols, 100);
+      rows = Math.min(rows, 100);
+
+      const cellW = Math.floor(fullW / cols);
+      const cellH = Math.floor(fullH / rows);
+      const originalExt = extname(filename) || ".png";
+      const baseName = filename.replace(/\.[^.]+$/, "");
+      const { sharpFormat, ext: outputExt } = resolveOutputFormat(
+        settings.outputFormat,
+        originalExt,
+      );
+
+      const archive = archiver("zip", { zlib: { level: 5 } });
+      const chunks: Buffer[] = [];
+      archive.on("data", (chunk: Buffer) => chunks.push(chunk));
+      const done = new Promise<void>((resolve, reject) => {
+        archive.on("end", resolve);
+        archive.on("error", reject);
+      });
+
+      for (let row = 0; row < rows; row++) {
+        for (let col = 0; col < cols; col++) {
+          let left: number;
+          let top: number;
+          let w: number;
+          let h: number;
+
+          if (settings.tileWidth && settings.tileHeight) {
+            left = col * settings.tileWidth;
+            top = row * settings.tileHeight;
+            w = col === cols - 1 ? fullW - left : Math.min(settings.tileWidth, fullW - left);
+            h = row === rows - 1 ? fullH - top : Math.min(settings.tileHeight, fullH - top);
+          } else {
+            left = col * cellW;
+            top = row * cellH;
+            w = col === cols - 1 ? fullW - left : cellW;
+            h = row === rows - 1 ? fullH - top : cellH;
+          }
+
+          if (left >= fullW || top >= fullH || w <= 0 || h <= 0) continue;
+
+          let pipeline = sharp(inputBuffer).extract({ left, top, width: w, height: h });
+          if (sharpFormat) {
+            const formatOpts: Record<string, unknown> = {};
+            if (sharpFormat === "jpeg" || sharpFormat === "webp") {
+              formatOpts.quality = settings.quality;
+            }
+            pipeline = pipeline.toFormat(sharpFormat, formatOpts);
+          }
+
+          const partBuffer = await pipeline.toBuffer();
+          archive.append(partBuffer, {
+            name: `${baseName}_r${row + 1}_c${col + 1}${outputExt}`,
+          });
+        }
+      }
+
+      await archive.finalize();
+      await done;
+
+      return {
+        buffer: Buffer.concat(chunks),
+        filename: `${baseName}_split.zip`,
+        contentType: "application/zip",
+      };
+    },
+  });
 }