Rust-first architecture and workspace skeleton

[Zhanfg]

Starts the production rewrite on a branch independent from the LSPosed Domo probe.

This draft establishes:

• the Rust workspace and crate boundaries;
• a versioned protobuf-compatible IPC envelope;
• task routing and fail-open state machine;
• segmented-range planning primitives;
• a panic-contained Rust FFI runtime boundary;
• Rust daemon and CLI entrypoints;
• a deliberately thin C++ Zygisk ABI shim;
• architecture and implementation-phase documentation;
• format, clippy and unit-test CI.

This is an architectural skeleton, not yet an installable module. The next implementation milestone is the companion-to-daemon FD bootstrap and Android arm64 build pipeline.