Proper start for README

README.md

@@ -1,25 +1,95 @@
 # App Versions
 
-A template to get started with Nextcloud app development.
+**Browse every installed app. Inspect available releases. Jump to the exact version you want.**
 
-## Usage
+`App Versions` is a Nextcloud admin tool for exploring installed apps and switching to a specific release from the app store metadata. It is built for local development stacks, debugging sessions, upgrade rehearsals, and those moments where "latest" is not good enough.
 
-- To get started easily use the [Appstore App generator](https://apps.nextcloud.com/developer/apps/generate) to
-  dynamically generate an App based on this repository with all the constants prefilled.
-- Alternatively you can use the "Use this template" button on the top of this page to create a new repository based on
-  this repository. Afterwards adjust all the necessary constants like App ID, namespace, descriptions etc.
+Instead of a plain selector, the UI opens with a searchable card grid of installed apps. Each card shows the app name, id, icon, and summary so you can move fast without guessing.
 
-Once your app is ready follow the [instructions](https://nextcloudappstore.readthedocs.io/en/latest/developer.html) to
-upload it to the Appstore.
+## What It Does
 
-## Resources
+- Lists installed apps in a full-width card view with search and filters.
+- Pulls app metadata such as title, summary, description, and preview icon.
+- Shows available versions for a selected app.
+- Supports install, update, and downgrade flows from the same screen.
+- Includes a dry-run mode with debug output for safer testing.
+- Warns about downgrade ranges and lets admins confirm intentionally.
+- Marks protected core apps in the picker and blocks management of them in the backend.
 
-### Documentation for developers:
+## Guard Rails
 
-- General documentation and tutorials: https://nextcloud.com/developer
-- Technical documentation: https://docs.nextcloud.com/server/latest/developer_manual
+This app is intentionally opinionated.
 
-### Help for developers:
+- `app_versions` cannot manage itself.
+- always-enabled Nextcloud core apps are shown in the card view, but clearly marked as `CORE`
+- protected apps do not expose a `Choose app` action
+- backend checks still reject direct requests against protected apps
 
-- Official community chat: https://cloud.nextcloud.com/call/xs25tz5y
-- Official community forum: https://help.nextcloud.com/c/dev/11
+That means the UI is honest and the backend is not trusting the UI.
+
+## Interface Snapshot
+
+The flow is intentionally split in two modes:
+
+1. **Discovery mode**
+   Search and browse the app cards across the full page width.
+2. **Action mode**
+   After selecting an app, the screen switches to the familiar split view for version inspection, install actions, and debug/result output.
+
+Extra controls live above the search:
+
+- update channel
+- safe mode
+- install dry-run
+- core app visibility filter
+
+## Why You'd Use It
+
+- reproduce a customer issue on an older app release
+- validate an upgrade path before touching production
+- compare app-store availability with what is installed locally
+- dry-run version changes and inspect the installer debug output
+- keep sharp boundaries around Nextcloud core apps
+
+## Development
+
+Frontend:
+
+```bash
+cd app_versions
+npm install
+npm run build
+```
+
+Useful frontend commands:
+
+```bash
+npm run watch
+npm run lint
+npm run stylelint
+```
+
+Backend quality checks:
+
+```bash
+composer install
+composer lint
+composer test:unit
+composer psalm
+```
+
+## Stack
+
+- Vue 3
+- `@nextcloud/vue`
+- Vite
+- PHP 8.1+
+- Nextcloud app framework
+
+## Status
+
+This app is currently shaped as an admin-focused utility for development and controlled environments. It is useful precisely because it gives more direct power than the default app management flow, so the protected-app restrictions are part of the design, not an afterthought.
+
+## License
+
+AGPL-3.0-or-later