fix: New README, new documentation for developpers, and many install.sh and update.sh fixes

doc/Developpers.md

@@ -0,0 +1,57 @@
+# Developpers documentation
+
+## Repository structure
+ 
+```
+dotfiles/
+├── install.sh
+├── scripts/
+│   └── update.sh               ← dotfiles-update
+├── packages/
+│   ├── core.pkgs               ← always installed
+│   ├── desktop.pkgs            ← always installed (automatic)
+│   ├── aur.pkgs                ← AUR packages (paru)
+│   ├── intel-cpu.pkgs          ← auto: Intel CPU
+│   ├── amd-cpu.pkgs            ← auto: AMD CPU
+│   ├── intel-gpu.pkgs          ← auto: Intel GPU
+│   ├── amd-gpu.pkgs            ← auto: AMD GPU
+│   ├── nvidia.pkgs             ← auto: NVIDIA GPU
+│   ├── gaming.pkgs             ← optional
+│   ├── development.pkgs        ← optional
+│   ├── ...
+│   ├── optional.groups         ← lists which groups are optional
+│   └── <group>.desc            ← one-line description shown in installer
+└── config/                     ← stow package; mirrors $HOME
+    ├── .config/
+    │   ├── hypr/
+    │   ├── waybar/
+    │   │   ├── vertical/
+    │   │   └── horizontal/
+    │   ├── rofi/
+    │   └── ...
+    └── .local/
+        └── bin/
+            └── atlas-update
+```
+ 
+### Package group conventions
+ 
+| File | When installed |
+|---|---|
+| `core.pkgs` | Always |
+| Any unlisted `*.pkgs` (e.g. `desktop.pkgs`) | Always (automatic) |
+| `aur.pkgs` | Always, via paru |
+| `intel-gpu.pkgs`, `amd-gpu.pkgs`, etc. | Auto-detected via `lspci` / `/proc/cpuinfo` |
+| Groups listed in `optional.groups` | User-chosen during install, remembered on updates |
+ 
+To add a new automatic group: create `packages/mygroup.pkgs` and commit.
+To add a new optional group: also add its name to `packages/optional.groups` and optionally a `packages/mygroup.desc` one-liner.
+ 
+
+## Package state tracking
+ 
+After each install or update, a snapshot of every installed group is saved to `~/.dotfiles/.state/packages/<group>`. On the next run, each group is diffed:
+ 
+- **New packages** in the `.pkgs` file → installed automatically
+- **Removed packages** → you are asked before uninstalling
+Delete `~/.dotfiles/.state/` to reset all state and force a full reinstall on the next update.