📝 clarify runtime file export examples

docs/api/file-sink-policy-to-json.md

@@ -56,10 +56,11 @@ In this example, the runtime file policy becomes a reusable structured value.
 
 When current and default policy should be exported separately:
 ```moonbit
-let current = file_sink_policy_to_json(sink.policy())
+let current = file_sink_policy_to_json(runtime.file_policy())
+let defaults = file_sink_policy_to_json(runtime.file_default_policy())
 ```
 
-In this example, callers can compare policy snapshots without formatting text first.
+In this example, callers can compare current and default policy snapshots without formatting text first.
 
 ### Error Case
 

docs/api/file-sink-state-to-json.md

@@ -56,10 +56,10 @@ In this example, callers receive a structured file-state snapshot instead of pla
 
 When support tooling should ingest file sink state programmatically:
 ```moonbit
-let snapshot = file_sink_state_to_json(state)
+let snapshot = file_sink_state_to_json(runtime.file_state())
 ```
 
-In this example, the helper exposes all major file-state fields in machine-readable form.
+In this example, the helper exposes all major live file-state fields in machine-readable form.
 
 ### Error Case
 

docs/api/runtime-file-state-to-json.md

@@ -55,10 +55,16 @@ In this example, callers receive a machine-readable combined runtime snapshot.
 
 When queued file runtime data should be embedded into a larger JSON object:
 ```moonbit
-let payload = runtime_file_state_to_json(state)
+match runtime.file_runtime_state() {
+  Some(snapshot) => {
+    let payload = runtime_file_state_to_json(snapshot)
+    ignore(payload)
+  }
+  None => ()
+}
 ```
 
-In this example, the helper keeps file-plus-queue diagnostics in one reusable JSON value.
+In this example, the helper keeps file-plus-queue diagnostics in one reusable JSON value after the optional runtime snapshot is read.
 
 ### Error Case
 

docs/api/stringify-runtime-file-state.md

@@ -48,10 +48,13 @@ Here are some specific examples provided.
 
 When a queued file runtime snapshot should be printed directly:
 ```moonbit
-println(stringify_runtime_file_state(snapshot, pretty=true))
+match runtime.file_runtime_state() {
+  Some(snapshot) => println(stringify_runtime_file_state(snapshot, pretty=true))
+  None => ()
+}
 ```
 
-In this example, both file state and queue metrics are shown in one readable JSON payload.
+In this example, both file state and queue metrics are shown in one readable JSON payload after the optional runtime snapshot is checked.
 
 #### When Need Compact Runtime Snapshot Export