feat(picker2): complete Picker2 prototype

Picker2 replaces the original Picker1 with a two-phase (tag → pick) +
mask-bitmap architecture, decoupling argument matching from type
conversion via a composable matcher pipeline.

Architecture
- FlagMatcher — boolean flags (--verbose)
- ArgMatcher — single flag+value pairs (--name Alice)
- MultiArgMatcher — multi-value flag groups (--files a.txt b.txt)
- PositionalMatcher — positional arguments, respects `--`
- SingleMatcher — composite for Single-type Pickables

Types
- Flag (Active/Inactive) — semantic bool flag value
- String + 14 numeric types via SinglePickable trait
- Vec<T> — greedy multi-value (all SinglePickable types)
- VecUntil<T> — bounded multi-value via BoundaryCheck trait
- VecUntil<T>, pick_string, pick_numbers, pick_bool, pick_flag

Style system
- UNIX_STYLE (kebab), POWERSHELL_STYLE (Pascal), WINDOWS_STYLE (Pascal)
- naming_case auto-conversion via just_fmt integration
- Style-aware separator (= for Unix, : for PS/Windows)

Infrastructure
- internal_repeat! macro generates PickerPattern1..=32
- SinglePickable blanket impl → Pickable
- MultiPickableWithBoundary trait with greedy/bounded variants
- 151 integration tests
- Docs updated for parser feature

1 files changed, 23 insertions, 0 deletions

diff --git a/mingling_picker/test/src/lib.rs b/mingling_picker/test/src/lib.rs
new file mode 100644
index 0000000..eac6cad
--- /dev/null
+++ b/mingling_picker/test/src/lib.rs
@@ -0,0 +1,23 @@
+// Using `assert_eq!(x, true)` is clearer than `assert!(x)` for expressing expected values
+//
+// BECAUSE `assert!` only checks if the boolean value is true,
+// while `assert_eq!` explicitly shows the expected value
+#![allow(clippy::bool_assert_comparison)]
+
+#[cfg(test)]
+mod test;
+
+use mingling_picker::parselib::MaskedArg;
+
+/// Create a single `MaskedArg` from a raw string and its original index.
+pub fn make_masked(raw: &str, idx: usize) -> MaskedArg<'_> {
+    MaskedArg { raw, raw_idx: idx }
+}
+
+/// Create a `Vec<MaskedArg>` from an array of `(raw, raw_idx)` pairs.
+pub fn make_args<'a>(pairs: &'a [(&'a str, usize)]) -> Vec<MaskedArg<'a>> {
+    pairs
+        .iter()
+        .map(|&(raw, idx)| MaskedArg { raw, raw_idx: idx })
+        .collect()
+}