Add config loading and dry-run validation

docs/cli.md

@@ -3,10 +3,10 @@
 ## Shortest useful command
 
 ```sh
-go run ./cmd/distributor --help
+go run ./cmd/distributor run --config examples/local-to-local.yml --dry-run
 ```
 
-This prints the currently implemented command shell.
+This loads and validates the example config, then prints the resolved pipeline summary without publishing files.
 
 ## Command overview
 
@@ -20,7 +20,9 @@ distributor inspect
 
 `version` prints the application name and version. The default development version is `dev`; release builds may replace it at build time.
 
-`run`, `validate`, and `inspect` are command placeholders. They intentionally fail with a clear `not implemented` error until the corresponding application behavior exists.
+`run --config <path> --dry-run` loads and validates configuration, then prints a concise summary of configured pipelines and destinations. It does not discover bundles or publish files yet.
+
+`run` without `--dry-run`, `validate`, and `inspect` intentionally fail with a clear `not implemented` error until the corresponding application behavior exists.
 
 ## Flag reference
 
@@ -28,6 +30,19 @@ The root command supports:
 
 - `--help`, `-h`: print root help.
 
-Each implemented subcommand supports:
+Each subcommand supports:
 
 - `--help`, `-h`: print command-specific help.
+
+`run` supports:
+
+- `--config <path>`: config file to load.
+- `--dry-run`: validate config and print the resolved summary without publishing.
+
+## Common workflows
+
+Validate a config file without publishing:
+
+```sh
+go run ./cmd/distributor run --config examples/local-to-local.yml --dry-run
+```