Add `mingling_pathf` sub-crate and `pathf` feature for automatic
resolution of Mingling type module paths at build time. Scans source
files, identifies macro invocations via pattern matchers, and generates
mapping files consumed by `gen_program!()`.

Add a `PatternAnalyzer` with an `AnalyzePattern` trait to detect and
extract struct declarations from Rust source files, supporting nested
inline modules.

Introduce the core pathfinding infrastructure with `ModulePathMapping`,
`MappingItem`, and `MinglingPathfinderError` types. Support recursive
module traversal, `pub use` re-export hoisting, and standard Rust
module resolution rules.