feat(environments): env CRUD, workspace switcher, CLI + MCP parity (#68)

Environment lanes existed as seeded rows (production/preview/development)
with a per-service environment label, but there was no way to list,
create, or delete them. Adds the management surface and the switcher:

- GET /projects/:id/environments with live service counts (sqlc)
- POST /projects/:id/environments — lowercase dns-label names, 1-50
  chars, unique per project (409 on dupe)
- DELETE /environments/:id — refuses while it holds services (409)
- Workspace service list gains env filter chips with counts plus an
  inline "+ env" creator
- CLI: containr environments list|create|delete (--yes on delete);
  MCP: containr_environments_list/create/delete (delete needs confirm)
- OpenAPI: new Environments tag + ProjectEnvironment schema

Live-verified: list counts, name validation, dupe 409, empty delete,
non-empty 409, CLI list.

Generated with [Devin](https://devin.ai)

Co-authored-by: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>

app/frontend/src/generated/api-types.ts

@@ -9391,6 +9391,137 @@ export interface paths {
         patch?: never;
         trace?: never;
     };
+    "/projects/{id}/environments": {
+        parameters: {
+            query?: never;
+            header?: never;
+            path?: never;
+            cookie?: never;
+        };
+        /**
+         * List project environments
+         * @description Returns each environment lane with a live service count — the data behind the environment switcher.
+         */
+        get: {
+            parameters: {
+                query?: never;
+                header?: never;
+                path: {
+                    /** @description Project ID */
+                    id: components["parameters"]["ProjectIdParam"];
+                };
+                cookie?: never;
+            };
+            requestBody?: never;
+            responses: {
+                /** @description Project environments */
+                200: {
+                    headers: {
+                        [name: string]: unknown;
+                    };
+                    content: {
+                        "application/json": {
+                            environments?: components["schemas"]["ProjectEnvironment"][];
+                        };
+                    };
+                };
+            };
+        };
+        put?: never;
+        /**
+         * Create an environment
+         * @description Adds a named environment lane. Names are lowercase alphanumeric with dashes, 1-50 chars, unique per project.
+         */
+        post: {
+            parameters: {
+                query?: never;
+                header?: never;
+                path: {
+                    /** @description Project ID */
+                    id: components["parameters"]["ProjectIdParam"];
+                };
+                cookie?: never;
+            };
+            requestBody: {
+                content: {
+                    "application/json": {
+                        name: string;
+                    };
+                };
+            };
+            responses: {
+                /** @description Created environment */
+                201: {
+                    headers: {
+                        [name: string]: unknown;
+                    };
+                    content: {
+                        "application/json": {
+                            environment?: components["schemas"]["ProjectEnvironment"];
+                        };
+                    };
+                };
+                /** @description Environment already exists */
+                409: {
+                    headers: {
+                        [name: string]: unknown;
+                    };
+                    content?: never;
+                };
+            };
+        };
+        delete?: never;
+        options?: never;
+        head?: never;
+        patch?: never;
+        trace?: never;
+    };
+    "/environments/{id}": {
+        parameters: {
+            query?: never;
+            header?: never;
+            path?: never;
+            cookie?: never;
+        };
+        get?: never;
+        put?: never;
+        post?: never;
+        /**
+         * Delete an empty environment
+         * @description Removes an environment lane; fails with 409 while it still holds services.
+         */
+        delete: {
+            parameters: {
+                query?: never;
+                header?: never;
+                path: {
+                    id: string;
+                };
+                cookie?: never;
+            };
+            requestBody?: never;
+            responses: {
+                /** @description Environment deleted */
+                200: {
+                    headers: {
+                        [name: string]: unknown;
+                    };
+                    content?: never;
+                };
+                /** @description Environment still contains services */
+                409: {
+                    headers: {
+                        [name: string]: unknown;
+                    };
+                    content?: never;
+                };
+            };
+        };
+        options?: never;
+        head?: never;
+        patch?: never;
+        trace?: never;
+    };
     "/projects/{id}/preview-environments": {
         parameters: {
             query?: never;
@@ -12488,6 +12619,18 @@ export interface components {
             restart_policy?: Record<string, never>;
             health_check?: Record<string, never>;
         };
+        ProjectEnvironment: {
+            /** Format: uuid */
+            id?: string;
+            name?: string;
+            /** Format: uuid */
+            project_id?: string;
+            service_count?: number;
+            /** Format: date-time */
+            created_at?: string;
+            /** Format: date-time */
+            updated_at?: string;
+        };
         PreviewEnvironment: {
             /** Format: uuid */
             id?: string;