feat: harden Rust runtime and IM bridge parity

[waterbang]

What changed

• hardens Rust terminal history/replay and runtime restoration, and allows multiple groups to share one scope directory
• aligns Python/Rust IM authorization, lifecycle, streaming, long-message, and attachment delivery across Telegram, Discord, Slack, Feishu, DingTalk, WeCom, and Weixin
• adds Discord Gateway proxy support, Weixin login/verification recovery, safer IM visibility filtering, and persistent logout/revoke handling
• streamlines Web Model connector UX and synchronizes UI contracts, documentation, CI, and tests

Why

Rust is becoming the primary CCCC implementation, but several lifecycle, replay, authorization, delivery, and cross-platform behaviors still diverged from Python. Those gaps caused lost terminal history, duplicate or dropped IM messages, stalled login flows, inaccessible Discord Gateway connections behind proxies, and inconsistent group creation behavior.

Impact

• Rust restores active terminal history and IM workers more reliably after restart.
• IM replies are progressively delivered or losslessly chunked without leaking internal notifications.
• Legacy authorization state remains compatible.
• Users can create multiple groups in one directory and connect Web Model/MCP flows with simpler UI.

Validation

• cargo fmt --all --check
• cargo clippy --workspace --all-targets -- -D warnings
• Rust workspace and daemon CI-equivalent test suites
• Python: 2676 passed, 8 skipped, 1 deselected
• Web: check/typecheck, 1078 tests, production build
• pre-commit impacted checks: all passed