chore: remove dead broker mode code

[khaliqgant]

Summary

• Removes the dead integrated broker server (server.ts) and all 23 files exclusively used by it (~7,700 lines deleted)
• Removes unused dependencies: @agent-relay/storage, @agent-relay/protocol, @agent-relay/utils
• All entry points already route through proxy-server.ts — broker mode was completely dead code

What was removed

• Core: server.ts (the integrated broker server entry point)
• Routes (11 files): auth, messaging, history, channels-integrated, decisions, tasks, fleet, spawn, system, settings, ui
• Libraries (7 files): server-state, channel-state, broadcast, websocket-runtime, attachment-storage, cli-auth, data-assembly
• Services (2 files): broker-spawn-reader, user-bridge
• WebSocket (3 files): main, bridge, presence
• Cleaned up: types/index.ts, services/index.ts, websocket/logs.ts (removed setupLogsWebSocket)

Test plan

• TypeScript typecheck passes (tsc --noEmit)
• All 210 tests pass across 15 test files
• Verify dashboard runs correctly in standalone/proxy mode

🤖 Generated with Claude Code

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