SSE en formato Claude Code CLI via ?format=claude

Nuevo ClaudeFormatEmitter traduce eventos nativos al formato exacto
que produce Claude Code CLI: content_block_start/delta/stop, tool_result,
assistant snapshots, result con usage/cost, done.

- streaming/claude_format.py: ClaudeFormatEmitter + DualEmitter
- base.py: enriquecer eventos con tool_call_id, raw_output, tool_arguments
- engine.py: usage/cost en EXECUTION_COMPLETED
- routes.py: ?format=claude en /sessions/{id}/stream
- main.py: DualEmitter wiring (emite a ambos formatos)

El frontend puede consumir el stream sin cambios — mismos event types
que Claude Code CLI. El formato nativo sigue disponible para el dashboard.

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

src/main.py

@@ -27,6 +27,7 @@ from .mcp.registry import MCPRegistry
 from .memory.store import MemoryStore
 from .orchestrator.engine import OrchestratorEngine
 from .storage.redis import RedisStorage
+from .streaming.claude_format import ClaudeFormatEmitter, DualEmitter
 from .streaming.sse import SSEEmitter
 
 logging.basicConfig(
@@ -38,6 +39,8 @@ logger = logging.getLogger(__name__)
 # Global instances (initialized in lifespan)
 redis_storage = RedisStorage()
 sse_emitter = SSEEmitter(redis_storage=redis_storage)
+claude_emitter = ClaudeFormatEmitter()
+dual_emitter = DualEmitter(sse_emitter, claude_emitter)
 mcp_registry = MCPRegistry()
 
 
@@ -48,7 +51,6 @@ async def lifespan(app: FastAPI):
 
     # 1. Connect Redis
     await redis_storage.connect()
-    sse_emitter.set_storage(redis_storage)
 
     # 2. Initialize model adapter
     if settings.default_model_provider == "openai":
@@ -82,12 +84,14 @@ async def lifespan(app: FastAPI):
     mcp_registry.load_config()
 
     # 6. Wire dependencies (orchestrator is created per-message with session's MCP)
+    dual_emitter.set_storage(redis_storage)
     set_dependencies(
         storage=redis_storage,
         model_adapter=model_adapter,
         context_engine=context_engine,
         memory_store=memory_store,
-        sse_emitter=sse_emitter,
+        sse_emitter=dual_emitter,
+        claude_emitter=claude_emitter,
         mcp_registry=mcp_registry,
     )