chore(deps): Remove unused heavy AI/ML dependencies from package.json

Remove large dependencies that are not actively used in the codebase:
- jszip: Unused ZIP processing library
- pdfjs-dist: PDF rendering (handled by external library)
- @techstark/opencv-js: Computer vision operations
- @tensorflow/tfjs: TensorFlow.js machine learning framework
- @tensorflow-models/coco-ssd: COCO-SSD object detection model

These dependencies were related to experimental features that have been
replaced or moved to external processing. Removing them significantly
reduces bundle size and simplifies the dependency tree.

Retain only actively used dependencies like htmx, chart.js, lunr,
and the @bookhoard/foliate-js fork with panel detection support.

package.json

@@ -16,12 +16,7 @@
     "chart.js": "^4.5.1",
     "highlight.js": "^11.11.1",
     "htmx.org": "^2.0.8",
-    "jszip": "3.10.1",
     "lunr": "^2.3.9",
-    "pdfjs-dist": "^5.6.205",
-    "@techstark/opencv-js": "^4.12.0-release.1",
-    "@tensorflow/tfjs": "^4.22.0",
-    "@tensorflow-models/coco-ssd": "^2.2.3",
     "@bookhoard/foliate-js": "github:john-okeefe/foliate-js#bookhoard-panel-detection"
   },
   "devDependencies": {