docs: update API docs for external repositories and git mounts

- Add GET /repositories endpoint documentation
- Add POST /repositories endpoint for external repos
- Update config-profiles.md with git mount details
- Update repositories.md with external repo support

docs/api/repositories.md

@@ -8,6 +8,73 @@ All endpoints require authentication (session cookie).
 
 ---
 
+## GET /repositories
+
+**Description:** List all repositories owned by the user, including external repositories not tied to any project.
+
+### Response
+
+#### Success (200 OK)
+
+```json
+[
+  {
+    "id": "uuid",
+    "name": "my-external-repo",
+    "remote_url": "https://github.com/user/repo.git",
+    "is_mirror": false,
+    "project_id": null,
+    "owner_id": "uuid",
+    "created_at": "2024-01-01T00:00:00Z"
+  }
+]
+```
+
+---
+
+## POST /repositories
+
+**Description:** Create a new external repository (not tied to any project). External repositories can be used across all projects for config profile git mounts.
+
+### Request
+
+#### Request Body
+
+```json
+{
+  "name": "my-external-repo",
+  "remote_url": "https://github.com/user/repo.git",
+  "ssh_key_id": "uuid"
+}
+```
+
+| Field | Type | Required | Description |
+|-------|------|----------|-------------|
+| `name` | `string` | Yes | Repository name (unique per user for external repos) |
+| `remote_url` | `string` | No | Remote URL to clone from |
+| `ssh_key_id` | `string` | No | SSH key ID for authentication |
+| `force_original_url` | `boolean` | No | Skip URL parsing (default: false) |
+
+### Response
+
+#### Success (201 Created)
+
+```json
+{
+  "id": "uuid",
+  "name": "my-external-repo",
+  "path": "/data/repos/external/{user_id}/{repo_id}",
+  "remote_url": "https://github.com/user/repo.git",
+  "is_mirror": false,
+  "project_id": null,
+  "owner_id": "uuid",
+  "ssh_key_id": "uuid",
+  "created_at": "2024-01-01T00:00:00Z"
+}
+```
+
+---
+
 ## GET /projects/{project_id}/repositories
 
 **Description:** List repositories in a project.