docs: comprehensive documentation overhaul

Add complete documentation structure:
- Frontend architecture documentation
- Database schema documentation
- Deployment guides (Docker, Traefik, Authentik, Environment)
- Development guides (Setup, Testing, Contributing, Quality Gates)
- Deployment architecture documentation
- Updated docs README with complete navigation

All new features and APIs are now documented.
Quality gates: docs only, no code changes

docs/features/repositories.md

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+# Git Repositories
+
+## Overview
+
+Git repositories are managed within projects. You can create bare repositories for new projects or clone existing repositories from remote sources.
+
+## How to Use
+
+### Creating a Repository
+
+1. Navigate to a **project workspace** or the **Repositories** page
+2. Click the **"New Repository"** button
+3. Fill in the form:
+   - **Name**: Repository name (required)
+   - **Remote URL**: For cloning (optional)
+   - **Mirror Clone**: Toggle for mirror clones
+4. Click **"Create Repository"**
+
+#### Bare Repository (No Remote URL)
+
+Creates a new bare git repository. Use this for:
+- New projects
+- Local-only repositories
+- Repositories that will be pushed to later
+
+#### Clone from Remote
+
+Enter a git URL to clone from:
+- `https://github.com/user/repo.git`
+- `git@github.com:user/repo.git`
+- `https://gitlab.com/user/repo.git`
+
+**Smart URL Parsing:** If you paste a browser URL (like `https://github.com/user/repo/tree/main`), the system will automatically suggest the correct git URL.
+
+#### Mirror Clone
+
+Enable **"Mirror Clone"** to create a full mirror of a remote repository:
+- Clones all branches and tags
+- Sets up remote tracking
+- Updates can be fetched later
+
+### Smart URL Parsing
+
+When pasting URLs, the system automatically detects browser URLs and suggests the correct git clone URL:
+
+**Examples:**
+- `https://github.com/user/repo/tree/main` → `https://github.com/user/repo.git`
+- `https://github.com/user/repo/blob/main/README.md` → `https://github.com/user/repo.git`
+- `https://gitlab.com/user/repo/-/tree/develop` → `https://gitlab.com/user/repo.git`
+
+You can accept the suggestion or proceed with the original URL.
+
+### Viewing Repositories
+
+The Repositories page shows all repositories in a project:
+- Repository name
+- Clone URL
+- Mirror status
+- Creation date
+
+### Repository Actions
+
+Each repository card provides:
+- **History**: View commit history and branch graph
+- **Browse**: Open in workspace file browser
+- **Delete**: Remove the repository
+
+### Deleting a Repository
+
+1. Click the **menu icon** (⋮) on a repository card
+2. Select **"Delete"**
+3. Confirm the deletion
+
+**Note:** This permanently deletes the repository from disk. This action cannot be undone.
+
+## API Reference
+
+### Endpoints
+
+- `GET /projects/{id}/repositories` - List repositories
+- `POST /projects/{id}/repositories` - Create repository
+- `DELETE /projects/{id}/repositories/{id}` - Delete repository
+- `POST /projects/{id}/repositories/parse-url` - Parse and validate URL
+
+See [Repositories API](../api/repositories.md) for detailed endpoint documentation.
+
+## Related Features
+
+- [Repository Workspace](workspace.md) - Browse repository files
+- [Git History](git-history.md) - View commit history
+- [Smart Git URL Parsing](repositories.md#smart-url-parsing) - Automatic URL correction