chore: drop JPEGDEC patch in favour of upstream fix (#1465)

## Summary

The progressive JPEG fixes (AC table skip, MCU_SKIP guard) from PR #1136
have been fixed upstream in bitbank2/JPEGDEC@8628297. Pin to that commit
and remove the pre-build patch script.

## Additional Context

Tested on Strange Pictures epub

---

### AI Usage

While CrossPoint doesn't have restrictions on AI tools in contributing,
please be transparent about their usage as it
helps set the right context for reviewers.

Did you use AI tools to help write this code? _**< PARTIALLY >**_

platformio.ini

@@ -50,7 +50,6 @@ board_build.partitions = partitions.csv
 extra_scripts =
   pre:scripts/build_html.py
   pre:scripts/gen_i18n.py
-  pre:scripts/patch_jpegdec.py
   pre:scripts/git_branch.py
 
 ; Libraries
@@ -62,7 +61,7 @@ lib_deps =
   bblanchon/ArduinoJson @ 7.4.2
   ricmoo/QRCode @ 0.0.1
   bitbank2/PNGdec @ ^1.0.0
-  bitbank2/JPEGDEC @ ^1.8.0
+  https://github.com/bitbank2/JPEGDEC.git#86282979224c8a32fd51e091ed5a35b0c699a52b
   links2004/WebSockets @ 2.7.3
 
 [env:default]