feat: add output filename suffixes, CPU fallback for GPU packages, and fix e2e tests

- Add tool-specific suffix to output filenames so downloads don't overwrite originals (batch & single-tool routes)
- Skip deleting shared models when uninstalling a bundle that shares models with another installed bundle
- Auto-detect NVIDIA GPU and swap GPU-only pip packages (onnxruntime-gpu, paddlepaddle-gpu) for CPU equivalents
- Refactor docker-compose with YAML anchors and explicit cpu/gpu profiles
- Add libheif-plugin-x265 to Dockerfile
- Fix install-all queue logic to handle concurrent individual installs and clear stale errors
- Unify playwright docker config to use same test dir with API_URL env var
- Fix flaky e2e selectors, rename Strip Metadata → Remove Metadata, handle collage custom dropzone, improve fallback test image generation

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

apps/api/src/routes/batch.ts

@@ -8,6 +8,7 @@
  * Returns a ZIP file containing all processed images.
  */
 import { randomUUID } from "node:crypto";
+import { extname } from "node:path";
 import { getBundleForTool, TOOL_BUNDLE_MAP } from "@ashim/shared";
 import archiver from "archiver";
 import type { FastifyInstance, FastifyReply, FastifyRequest } from "fastify";
@@ -170,7 +171,15 @@ export async function registerBatchRoutes(app: FastifyInstance): Promise<void> {
               }
               const result = await toolConfig.process(processBuffer, settings, processFilename);
 
-              results[index] = { buffer: result.buffer, filename: result.filename };
+              // Add tool suffix so downloads don't overwrite originals
+              let outFilename = result.filename;
+              if (outFilename === processFilename) {
+                const ext = extname(processFilename);
+                const base = ext ? processFilename.slice(0, -ext.length) : processFilename;
+                outFilename = `${base}_${toolId}${ext}`;
+              }
+
+              results[index] = { buffer: result.buffer, filename: outFilename };
 
               progress.completedFiles++;
               updateJobProgress({ ...progress });