feat(cli/sdk): expose /context usage data in non-interactive mode and SDK API (#2916)

* feat(cli): implement non-interactive /context output and diagnostic

- Extract collectContextData() from contextCommand.ts for shared usage.
- Register /context in ALLOWED_BUILTIN_COMMANDS_NON_INTERACTIVE.
- Extend SDK control protocol with GET_CONTEXT_USAGE request.
- Implement handleGetContextUsage in SystemController for programmatic token queries.
- Expose getContextUsage() method in the TypeScript SDK Query interface.

* fix: address review feedback and fix critical bugs in context usage feature

- Add missing `get_context_usage` route in ControlDispatcher (SDK calls would throw)
- Fix `executionMode` defaulting: use `?? 'interactive'` to match other commands
- Validate dynamic import of `collectContextData` before invoking
- Preserve original error message in handleGetContextUsage catch block
- Add ControlDispatcher test for get_context_usage routing
- Add JSDoc comment for context command in non-interactive allowlist

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* fix: re-check abort signal after async operations in handleGetContextUsage

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* docs: add getContextUsage() to SDK TypeScript documentation

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* docs: clarify getContextUsage showDetails is a display hint, not a data filter

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* fix: make showDetails affect response shape, add getContextUsage test

- When showDetails is false, return empty detail arrays instead of full
  data so /context and /context detail produce different payloads
- Add unit test for Query.getContextUsage() covering request payload
  and response handling

* fix: strip UI type from SDK response, sync Java SDK protocol

- Remove leaked `type: 'context_usage'` from control response payload
- Add GET_CONTEXT_USAGE to Java SDK protocol mirror (enum, interface,
  union type)

---------

Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

packages/sdk-java/qwencode/src/main/java/com/alibaba/qwen/code/cli/protocol/protocol.ts

@@ -372,6 +372,11 @@ export interface CLIControlSupportedCommandsRequest {
   subtype: 'supported_commands';
 }
 
+export interface CLIControlGetContextUsageRequest {
+  subtype: 'get_context_usage';
+  show_details?: boolean;
+}
+
 export type ControlRequestPayload =
   | CLIControlInterruptRequest
   | CLIControlPermissionRequest
@@ -381,7 +386,8 @@ export type ControlRequestPayload =
   | CLIControlMcpMessageRequest
   | CLIControlSetModelRequest
   | CLIControlMcpStatusRequest
-  | CLIControlSupportedCommandsRequest;
+  | CLIControlSupportedCommandsRequest
+  | CLIControlGetContextUsageRequest;
 
 export interface CLIControlRequest {
   type: 'control_request';
@@ -574,6 +580,7 @@ export enum ControlRequestType {
   INTERRUPT = 'interrupt',
   SET_MODEL = 'set_model',
   SUPPORTED_COMMANDS = 'supported_commands',
+  GET_CONTEXT_USAGE = 'get_context_usage',
 
   // PermissionController requests
   CAN_USE_TOOL = 'can_use_tool',