feat(docker): add migrate-config service for database migrations

* Include amcs-migrate-config binary in Docker image
* Document migration commands in README

README.md

@@ -654,6 +654,22 @@ Notes:
 - Database migrations `001` through `005` run automatically when the Postgres volume is created for the first time.
 - `migrations/006_rls_and_grants.sql` is intentionally skipped during container bootstrap because it contains deployment-specific grants for a role named `amcs_user`.
 
+### Run config migration with Compose
+
+The container image now includes `/app/amcs-migrate-config`.
+
+Dry-run (prints migrated YAML, does not write files):
+
+```bash
+docker compose --profile tools run --rm migrate-config --config /app/configs/dev.yaml --dry-run
+```
+
+Apply migration in-place (writes file + creates backup):
+
+```bash
+docker compose --profile tools run --rm migrate-config --config /app/configs/dev.yaml
+```
+
 ## Ollama
 
 Set your role targets to an Ollama provider to use a local or self-hosted Ollama server through its OpenAI-compatible API.