feat(jobs): expand environment variables in paths

README.md

@@ -126,7 +126,7 @@ relspec job run build-schema
 version: 1
 jobs:
   build-schema:
-    command: convert            # closed allow-list: convert | merge | scripts-list
+    command: convert            # closed allow-list: convert | merge | split | scripts-list | scripts-exec | templ | inspect | diff
     description: Merge the DBML sources and emit PostgreSQL DDL
     inputs:
       - path: schema/core.dbml
@@ -147,7 +147,9 @@ resolved relative to the job file and may not escape it, and remote database
 credentials are referenced by environment-variable name (`conn_env:`) and
 redacted from logs. The whole plan — unknown commands/formats, duplicate job
 names, missing inputs, path traversal, dependency cycles — is validated before
-any job runs. See [docs/JOB_FILES.md](docs/JOB_FILES.md).
+any job runs. Path-like fields also support `${NAME}` environment-variable
+references, which are expanded and safety-checked during pre-flight. See
+[docs/JOB_FILES.md](docs/JOB_FILES.md).
 
 ### `edit` — Interactive TUI editor