BUG-T9: Orphaned Web UI server process blocks port after MCP client disconnect or config change

[SoundBlaster]

Description

Fixes BUG-T9 by preventing orphaned wrapper processes from keeping the Web UI port bound after MCP client stdin disconnects.

Key changes:

• Added on_stdin_closed callback support to run_stdin_forwarder().
• Added terminate_bridge_process() with bounded shutdown behavior (SIGTERM then SIGKILL fallback after grace timeout).
• Wired a one-shot stdin-closed callback in main() to terminate the upstream bridge when stdin reaches EOF.
• Added/updated unit tests for EOF callback invocation, termination fallback behavior, and main-loop callback wiring.
• Completed FLOW artifacts for BUG-T9 (PRD, validation report, review report, archive index updates).

Validation summary:

• PYTHONPATH=src pytest → 659 passed, 5 skipped
• ruff check src/ → pass
• mypy src/ → pass
• PYTHONPATH=src pytest --cov=src/mcpbridge_wrapper --cov-report=term-missing → 91.52% total coverage

Type of Change

• Bug fix
• New feature
• Documentation update
• Refactoring
• CI/CD improvement

Quality Gates

Before submitting, ensure all quality gates pass:

make check

Or run individually:

• make test - All tests pass with ≥90% coverage
• make lint - No linting errors
• make format - Code is properly formatted
• make typecheck - Type checking passes
• make doccheck - Documentation is synced with DocC (if docs changed)

Documentation Sync

If you modified files in docs/, ensure corresponding DocC files are also updated:

docs/ file	DocC file
docs/installation.md	mcpbridge-wrapper.docc/Installation.md
docs/cursor-setup.md	mcpbridge-wrapper.docc/CursorSetup.md
docs/claude-setup.md	mcpbridge-wrapper.docc/ClaudeCodeSetup.md
docs/codex-setup.md	mcpbridge-wrapper.docc/CodexCLISetup.md
docs/troubleshooting.md	mcpbridge-wrapper.docc/Troubleshooting.md
docs/architecture.md	mcpbridge-wrapper.docc/Architecture.md
docs/environment-variables.md	mcpbridge-wrapper.docc/EnvironmentVariables.md
README.md	mcpbridge-wrapper.docc/mcpbridge-wrapper.md

• Documentation changes are synced with DocC catalog (or N/A)

Testing

• Added/updated tests for new functionality
• All tests pass locally
• Manually tested the changes

Checklist

• Code follows the project's style guidelines
• Self-review completed
• Comments added for complex code
• Documentation updated (if needed)
• No new warnings generated
• PR title is descriptive

[chatgpt-codex-connector]

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[chatgpt-codex-connector]

Preserve in-flight responses before terminating on stdin EOF

This callback force-terminates the upstream bridge as soon as stdin closes, which can kill requests that were just forwarded but not yet answered. In piped/one-shot usage (for example, writing a final JSON-RPC request and then closing stdin), on_stdin_closed runs immediately after forwarding and can terminate mcpbridge before the response is emitted, causing dropped output and a signal-style exit code instead of a normal response. Please drain pending responses (or at least close bridge.stdin first and wait briefly) before escalating to termination.

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