Wire realtime voice tool calls into OpenClaw

[rogerchappel]

Summary

• forward realtime provider tool calls through OpenClaw talk.client.toolCall
• add a relay API path that waits for the delegated chat final event and submits the tool result back to the realtime session
• replace the browser placeholder tool response with real openclaw_agent_consult delegation using the active session key

Verification

• pnpm test -- src/lib/gateway-client-realtime.test.ts 'src/app/api/runtimes/[id]/talk/realtime/relay/route.test.ts' src/lib/realtime-voice-client.test.ts src/lib/realtime-voice-audio.test.ts src/lib/runtime-capabilities.test.ts\n- pnpm typecheck\n- git diff --check\n- pre-push pnpm typecheck && pnpm build\n\n## Risk\nMedium. This changes realtime tool-call execution, but only for the realtime relay path and preserves explicit error tool results for unsupported or failed tool calls.