feat(cli,server): warn on deprecated config at load; scaffold version: 1

Surface the config deprecation notices at load: the CLI prints them via
`eprintln!` in `load_cli_config`; the server logs them via `tracing::warn!` in
`load_server_settings` (a no-op under tests with no subscriber). `omnigraph init`
now scaffolds a `version: 1` config using `storage:` instead of the legacy `uri:`.

Migrate the shared test fixtures (`support::local_yaml_config` →
`version: 1` + `storage:`; `remote_yaml_config` → `version: 1` + `servers:`/`server:`)
to the current schema so they don't trip the new warnings; the resolved `.uri` is
unchanged, so the tests behave identically. The no-`version:` notice is gated on a
loaded config file, so commands with a bare URI and no `omnigraph.yaml` stay quiet
(verified by the existing command-deprecation tests, which still pass). Extends the
`init` test for the scaffold shape and adds a legacy-config-warns test.

crates/omnigraph-server/src/lib.rs

@@ -918,6 +918,9 @@ pub fn load_server_settings(
     cli_allow_unauthenticated: bool,
 ) -> Result<ServerConfig> {
     let config = load_config(config_path)?;
+    for warning in config.deprecation_warnings() {
+        warn!("{warning}");
+    }
     let bind = cli_bind.unwrap_or_else(|| config.server_bind().to_string());
     // Either `--unauthenticated` or `OMNIGRAPH_UNAUTHENTICATED=1` flips
     // this. Treat any non-empty, non-"0"/"false" string as truthy —