feat: Add subagent_id attribute to devcontainer resource

- Add computed subagent_id attribute to devcontainer resource
- Generate unique UUID for subagent identification
- Add tests verifying subagent_id is a valid UUID
- Update documentation with new attribute

Author: DanielleMaywood

docs/resources/devcontainer.md

@@ -30,3 +30,4 @@ Define a Dev Container the agent should know of and attempt to autostart.
 ### Read-Only
 
 - `id` (String) The ID of this resource.
+- `subagent_id` (String) The ID of the subagent created for this Dev Container.

provider/devcontainer.go

@@ -17,6 +17,11 @@ func devcontainerResource() *schema.Resource {
 		CreateContext: func(_ context.Context, rd *schema.ResourceData, _ interface{}) diag.Diagnostics {
 			rd.SetId(uuid.NewString())
 
+			// Generate a unique subagent ID for this dev container.
+			if err := rd.Set("subagent_id", uuid.NewString()); err != nil {
+				return diag.FromErr(err)
+			}
+
 			return nil
 		},
 		ReadContext:   schema.NoopContext,
@@ -41,6 +46,11 @@ func devcontainerResource() *schema.Resource {
 				ForceNew:    true,
 				Optional:    true,
 			},
+			"subagent_id": {
+				Type:        schema.TypeString,
+				Description: "The ID of the subagent created for this Dev Container.",
+				Computed:    true,
+			},
 		},
 	}
 }

provider/devcontainer_test.go

@@ -4,6 +4,7 @@ import (
 	"regexp"
 	"testing"
 
+	"github.com/google/uuid"
 	"github.com/stretchr/testify/require"
 
 	"github.com/hashicorp/terraform-plugin-sdk/v2/helper/resource"
@@ -39,6 +40,11 @@ func TestDevcontainer(t *testing.T) {
 				} {
 					require.Equal(t, expected, script.Primary.Attributes[key])
 				}
+				// Verify subagent_id is a valid UUID.
+				subagentID := script.Primary.Attributes["subagent_id"]
+				require.NotEmpty(t, subagentID)
+				_, err := uuid.Parse(subagentID)
+				require.NoError(t, err, "subagent_id should be a valid UUID")
 				return nil
 			},
 		}},
@@ -72,6 +78,11 @@ func TestDevcontainerNoConfigPath(t *testing.T) {
 				} {
 					require.Equal(t, expected, script.Primary.Attributes[key])
 				}
+				// Verify subagent_id is a valid UUID.
+				subagentID := script.Primary.Attributes["subagent_id"]
+				require.NotEmpty(t, subagentID)
+				_, err := uuid.Parse(subagentID)
+				require.NoError(t, err, "subagent_id should be a valid UUID")
 				return nil
 			},
 		}},