feat: Pi CLI/SDK conformance fixes and structured debug logging

[NathanFlurry]

Summary

• Fix Pi PTY Ctrl+C, width/rendering, node tool capabilities, and shutdown behavior
• Add comprehensive Pi SDK coverage: session lifecycle, subprocess semantics, tool events, filesystem, network policy, permissions, path safety, resource cleanup
• Add Pi cross-surface parity, error reporting, config discovery, repo workflow, session resume, and worktree mutation tests
• Add OpenCode PTY real-provider test and SSRF protection with localhost RPC exemptions
• Add host-side PTY allocation for HostBinaryDriver and structured debug-log channel
• Fix WasmVM shell cwd propagation, path-based command dispatch, and PTY resize handling
• Audit and fix hardcoded monorepo dependency paths in publishable packages

Test plan

• Pi PTY tests pass (Ctrl+C, width, resize)
• Pi SDK tests pass (lifecycle, subprocess, tool events, filesystem, network, permissions, path safety, cleanup)
• Pi cross-surface parity and error reporting tests pass
• OpenCode PTY real-provider test passes
• SSRF protection tests pass
• WasmVM shell and terminal tests pass
• Existing test suite remains green