Add README, runbook, per-script docs, CHANGELOG and LICENSE.

Documents the organise-isos and generate-ventoy-json workflow end-to-end:
quick start in the README, full procedure with troubleshooting and recovery
in docs/RUNBOOK.md, and reference docs for each script covering parameters,
parsing rules, category groupings, and extensibility. Ships a YOLO licence
(no warranty) and seeds CHANGELOG.md for the v0.1.0 release.

README.md

@@ -0,0 +1,72 @@
+# ventoy-extras
+
+PowerShell helpers for keeping a tidy [Ventoy](https://www.ventoy.net/) USB
+drive. Drops a pile of randomly-named ISOs into a sensible directory tree, then
+generates a categorised `ventoy.json` so the boot menu groups them by OS family
+instead of vomiting one flat list.
+
+Two scripts, no dependencies beyond Windows PowerShell 5.1 (or PowerShell 7+).
+
+## Scripts
+
+| Script | Purpose |
+| --- | --- |
+| [`organise-isos.ps1`](organise-isos.ps1) | Parse ISO filenames, infer `os/version/arch`, move into `iso-library\<os>\<version>\<arch>\` |
+| [`generate-ventoy-json.ps1`](generate-ventoy-json.ps1) | Walk that tree and emit `ventoy.json` with a per-family submenu structure |
+
+## Quick start
+
+```powershell
+# 1. Drop all your downloaded ISOs into a working directory, then:
+.\organise-isos.ps1 -SourceDir .\downloads -DestDir .\iso-library -DryRun
+# Review the planned moves, then re-run without -DryRun
+.\organise-isos.ps1 -SourceDir .\downloads -DestDir .\iso-library
+
+# 2. Generate the ventoy menu config:
+.\generate-ventoy-json.ps1 -IsoRoot .\iso-library -OutFile .\ventoy.json
+
+# 3. Copy iso-library\ to the root of your Ventoy USB, and copy
+#    ventoy.json into the ventoy\ folder on that same drive.
+```
+
+That's the whole workflow. See [`docs/RUNBOOK.md`](docs/RUNBOOK.md) for the
+detailed operational walkthrough, and the per-script docs for the gory bits.
+
+## Documentation
+
+- [`docs/RUNBOOK.md`](docs/RUNBOOK.md) — end-to-end procedure, troubleshooting, recovery
+- [`docs/organise-isos.md`](docs/organise-isos.md) — parameters, naming rules, OS detection map
+- [`docs/generate-ventoy-json.md`](docs/generate-ventoy-json.md) — parameters, category groupings, menu layout
+- [`docs/directory-layout.md`](docs/directory-layout.md) — what the on-disk tree looks like and why
+
+## Directory layout produced
+
+```
+iso-library\
+  ubuntu\
+    24.04\
+      x86_64\
+        ubuntu-24.04.1-desktop-amd64.iso
+  debian\
+    12\
+      x86_64\
+        debian-12.5.0-amd64-netinst.iso
+  rocky\
+    9\
+      aarch64\
+        Rocky-9.3-aarch64-minimal.iso
+  ...
+```
+
+Three levels: OS slug, version, architecture. Ventoy follows directories
+transparently, so the same tree is what ends up on the USB.
+
+## Requirements
+
+- Windows PowerShell 5.1 or PowerShell 7+
+- A Ventoy USB drive (set up separately — see [ventoy.net](https://www.ventoy.net/))
+- Enough disk space to hold your ISO collection twice during reorganisation
+
+## License
+
+[YOLO LICENSE](LICENSE) — do whatever you want with it, no warranty, things may blow up.