refactor: unify type discovery and improve Rust type parsing

[ap-apely]

• Added support for snake_case keys in tauri.conf.json (e.g. project_path)
• Fixed enum type discovery (recursive parsing of tuple and struct variants)
• Improved Rust type parsing:

• module-qualified types (std::collections::HashMap)
• slices ([u8])
• fixed arrays ([u8; 32])

• Stripped lifetimes (e.g. 'a) from generic arguments to avoid unknown types in TypeScript
• Deduplicated events by name
• Fixed path filtering for .git and target using path components instead of string matching
• Unified type discovery logic and removed duplicate traversal in generators
• Added support for projects where src-tauri is the root directory

Previously, some valid Rust types were not parsed correctly.

For example:

#[derive(serde::Serialize)]
pub struct Example<'a> {
    pub data: &'a std::collections::HashMap<u64, Permissions>,
    pub bytes: &'a [u8],
}

Issues:

• lifetimes ('a) caused unknown types in TypeScript
• module-qualified types (std::collections::HashMap) were not resolved
• slices ([u8]) were not supported

Another case:

#[derive(serde::Serialize)]
#[serde(tag = "type", content = "data")]
pub enum Event<'a> {
    Message(&'a str),
}

Issues:

• enum variant types were not discovered recursively
• generated types were incomplete or missing

These cases are now handled correctly.

[thwbh]

Hi @ap-apely thank you for the contribution! Would you please create an issue, too, describing the problem your change fixes?
https://github.com/thwbh/tauri-typegen/issues

After that, I'll pick it up for the next version.