TUI freezes/hangs after LLM streaming completes

Description

The TUI freezes or hangs after LLM streaming completes. Several independent bugs contribute:

Stream never terminates: for await (stream.fullStream) in processor.ts doesn't break on the finish event — it only breaks on needsCompaction. After the LLM finishes streaming, the loop continues waiting indefinitely, causing a 0% CPU hang.
No timeout on client.listTools(): In mcp/index.ts, client.listTools() has no timeout wrapper. If an MCP server is unresponsive, this hangs indefinitely.
Unhandled effect rejections: In db.ts, fire-and-forget effects (effect()) can reject silently, causing unhandled promise rejections that propagate unpredictably.
SDK batch window too tight: The 16ms event batch window in sdk.tsx causes excessive render churn during high-throughput streaming (10+ tokens/sec), amplifying GC pressure.

TUI should remain responsive during and after streaming, and the stream loop should exit cleanly on the finish event.

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What needs to be fixed:

Missing system information: no OpenCode version, OS, or terminal specified — these are required fields in the bug report template
The description reads as AI-generated: it contains detailed internal code-level analysis (specific file names, function names, and implementation details like for await (stream.fullStream) in processor.ts, 16ms batch windows in sdk.tsx, etc.) with no actual reproduction evidence, logs, or personal system context. AI-generated walls of technical analysis are not acceptable per our contributing guidelines.
Steps to reproduce are too vague to be actionable ("run against a large project" with no version or environment details)

Please edit this issue to address the above within 2 hours, or it will be automatically closed.

This issue might be a duplicate of existing issues. Please check:

Random TUI freeze/hang with process continuing in background #12834: Similar TUI freeze/hang symptom with process continuing in background
Critical Stability Issues: App Freezing & Hanging Analysis #731: Broader analysis of app freezing and hanging issues including MCP-related hangs

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