refactor(rust): Split large modules into modular structure (#29)

* Add Bytes alias to ByteArray parameters for consistency

Add [Alias('Bytes')] to the -ByteArray parameter in:
- ConvertFrom-ByteArrayToString
- ConvertFrom-CompressedByteArrayToString

This matches the existing pattern in ConvertFrom-ByteArrayToBase64 and
ConvertFrom-ByteArrayToMemoryStream, providing a consistent API across
all functions that accept byte array input.

Fixes #25

* chore: Bump version to 2.0.6-alpha

* refactor: modularize base64 into focused modules

Split monolithic base64.rs (1,917 lines) into modular structure:
- encoding.rs: encoding conversion helpers (301 lines)
- string_ops.rs: string-based Base64 FFI functions (256 lines)
- bytes_ops.rs: byte array-based Base64 FFI functions (156 lines)
- mod.rs: module organization and re-exports (13 lines)

Benefits:
- Improved maintainability with clear separation of concerns
- Tests co-located with implementation (Rust best practice)
- Easier navigation with smaller, focused files
- All 184 tests passing with no breaking changes

* Optimize Rust dependencies with selective features and update to latest versions

- Disable default features for all dependencies to reduce bloat
- Enable only required features (std, alloc, rust_backend)
- Update chrono 0.4.42 -> 0.4.43
- Update flate2 1.1.5 -> 1.1.8
- Pin exact versions for reproducible builds
- All 184 tests pass

* refactor(rust): Split encoding.rs into modular structure

* refactor(rust): Split hash.rs into modular structure

* refactor(rust): Split compression.rs into modular structure

* style(rust): Apply cargo fmt formatting

Author: austoonz

lib/Cargo.lock

@@ -8,15 +8,15 @@ name = "convert_core"
 crate-type = ["cdylib"]
 
 [dependencies]
-base64 = "0.22"
-sha2 = "0.10"
-sha1 = "0.10"
-md-5 = "0.10"
-hmac = "0.12"
-flate2 = "1.0"
-percent-encoding = "2.3"
-chrono = "0.4"
+base64 = { version = "0.22.1", default-features = false, features = ["std"] }
+sha2 = { version = "0.10.9", default-features = false }
+sha1 = { version = "0.10.6", default-features = false }
+md-5 = { version = "0.10.6", default-features = false }
+hmac = { version = "0.12.1", default-features = false }
+flate2 = { version = "1.1.8", default-features = false, features = ["rust_backend"] }
+percent-encoding = { version = "2.3.2", default-features = false, features = ["alloc"] }
+chrono = { version = "0.4.43", default-features = false, features = ["std"] }
 
 [dev-dependencies]
-criterion = "0.5"
-proptest = "1.4"
+criterion = "0.5.1"
+proptest = "1.9.0"