docs: fix Linux deps and improve contribution setup instructions

- Replace obsolete libjpeg8-dev with libjpeg-dev (virtual metapackage,
  works on both Debian and Ubuntu); clarify that -dev headers are only
  needed when building Pillow from source, not for normal development
- Rewrite contribution setup to use `hatch shell` (consistent with other
  openZIM repos like ted, warc2zim, youtube); clarify that all commands
  must be run from the local clone root; add note on what pre-commit install does

Closes #152, Closes #153

Author: its-me-maady

CHANGELOG.md

@@ -17,6 +17,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Add proper typing @overload to `zimscraperlib.image.optimize_xxx` methods (#273)
 - Backport wabac.JS change around rewriting: detect when JS is in 'strict' mode and avoid using 'arguments' (#286)
 - Fix installation from source, which missed wombatSetup.js (#287)
+- Fix obsolete `libjpeg8-dev` reference, replace with `libjpeg-dev` and clarify dev headers are only needed when building Pillow from source (#152)
+- Improve contribution setup instructions: use `hatch shell`, clarify commands must be run from local clone root (#153)
 
 ### Changed
 

README.md

@@ -49,11 +49,16 @@ brew install libmagic wget libtiff libjpeg webp little-cms2 ffmpeg gifsicle
 
 ## Linux
 
+## Linux
+
 ```sh
-sudo apt install libmagic1 wget ffmpeg \
-    libtiff5-dev libjpeg8-dev libopenjp2-7-dev zlib1g-dev \
+# Minimal install (uses pre-built Pillow wheels — sufficient for most development)
+sudo apt install libmagic1 wget ffmpeg gifsicle
+
+# Only needed if building Pillow from source
+sudo apt install libtiff5-dev libjpeg-dev libopenjp2-7-dev zlib1g-dev \
     libfreetype6-dev liblcms2-dev libwebp-dev tcl8.6-dev tk8.6-dev python3-tk \
-    libharfbuzz-dev libfribidi-dev libxcb1-dev gifsicle
+    libharfbuzz-dev libfribidi-dev libxcb1-dev
 ```
 
 ## Alpine
@@ -68,11 +73,29 @@ This project adheres to openZIM's [Contribution Guidelines](https://github.com/o
 
 This project has implemented openZIM's [Python bootstrap, conventions and policies](https://github.com/openzim/_python-bootstrap/docs/Policy.md) **v1.0.2**.
 
+All instructions below must be run from the root of your local clone of this repository.
+
+If you do not already have it on your system, install [hatch](https://hatch.pypa.io/latest/install/):
+
 ```shell
 pip install hatch
-pip install ".[dev]"
+```
+
+Start a hatch shell — this will install all dependencies including dev in an isolated virtual environment:
+
+```shell
+hatch shell
+```
+
+Set up the pre-commit Git hook (runs linters automatically before each commit):
+
+```shell
 pre-commit install
-# For tests
+```
+
+Run tests with coverage:
+
+```shell
 invoke coverage
 ```