fix(cli): harden terminal process reliability

[limityan]

Summary

• exercise active-turn resize, continued rendering, cancellation, stream disconnect, and editable-input recovery through real PTY/ConPTY processes
• enforce stream-json patch-settlement ordering so success and write-failure paths each emit exactly one final terminal event
• make terminal restoration best-effort per step while preserving the primary initialization io::Error in the error chain
• isolate process tests from host BitFun profile roots and make the loopback model fixture deterministic on Windows
• align the existing CLI architecture and decomposition status with the verified Linux PTY and Windows ConPTY contracts

Product and architecture boundaries

• no CLI visual redesign, command, shortcut, DTO, public SDK, or runtime-owner change
• no extension/plugin or HarmonyOS scope
• the model fixture is a deterministic loopback OpenAI-compatible stream; real-provider approval flows remain explicitly out of scope
• macOS active-turn PTY validation and OS-level terminal initialization fault injection remain follow-up work

Validation

• cargo +1.95.0 test -p bitfun-cli (249 tests passed across unit and integration targets)
• cargo +1.95.0 check --workspace
• node scripts/check-core-boundaries.mjs
• pnpm run check:repo-hygiene
• git diff --check

Development note

AI-assisted and fully tested with the validation listed above.