[WIP] Fix type checking errors in ClaudeAgent

[Copilot]

Thanks for asking me to work on this. I will get started on it and keep this PR's description up to date as I form a plan and make progress.

Original prompt

2025-11-29T18:02:49.4529977Z [3/5] Fetching packages...
2025-11-29T18:02:54.7331891Z [4/5] Linking dependencies...
2025-11-29T18:02:55.2081256Z [5/5] Building fresh packages...
2025-11-29T18:02:55.3022792Z success Saved lockfile.
2025-11-29T18:02:55.3057899Z Done in 8.30s.
2025-11-29T18:02:55.3300593Z 🔨 Building project...
2025-11-29T18:02:55.5089667Z yarn run v1.22.22
2025-11-29T18:02:55.5292908Z $ tsc
2025-11-29T18:02:56.7915287Z ##[error]src/agent/ClaudeAgent.ts(138,20): error TS2367: This comparison appears to be unintentional because the types '"result" | "system" | "stream_event" | "tool_progress" | "auth_status"' and '"tool_result"' have no overlap.
2025-11-29T18:02:56.7924186Z ##[error]src/agent/ClaudeAgent.ts(138,54): error TS2367: This comparison appears to be unintentional because the types '"result" | "system" | "stream_event" | "tool_progress" | "auth_status"' and '"tool"' have no overlap.
2025-11-29T18:02:56.8156310Z error Command failed with exit code 2.
2025-11-29T18:02:56.8157591Z info Visit https://yarnpkg.com/en/docs/cli/run for documentation about this command.
2025-11-29T18:02:56.8272192Z ❌ Failed to build project
2025-11-29T18:02:56.8281161Z ##[error]Process completed with exit code 1.

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