feat: add dispatch strategy features with auto-selection and benchmark

support

Add `dispatch_linear`, `dispatch_tree`, and `dispatch_phf` as mutually
exclusive features for selecting the command dispatch strategy. When no
strategy feature is enabled, an auto-selection heuristic picks the
optimal strategy based on command table characteristics (size, name
length, nesting depth).

Add the `bench_support` feature to compile all three generators for the
benchmark harness, and introduce `bench_cell!` to generate benchmark
cells comparing strategies.

The PHF generator uses a CHD minimal perfect hash for O(1) lookup
independent of table size, while the trie generator was refactored to
use a shared fallback method, keeping code size linear in table size.

1 files changed, 4 insertions, 2 deletions

diff --git a/mingling_core/src/program/collection.rs b/mingling_core/src/program/collection.rs
index c571887..3ff065a 100644
--- a/mingling_core/src/program/collection.rs
+++ b/mingling_core/src/program/collection.rs
@@ -35,8 +35,10 @@ pub trait ProgramCollect {
 
     /// Dispatch the raw user arguments to an Entry.
     ///
-    /// The concrete matching strategy (trie or linear list) is generated by
-    /// `gen_program!` and selected by the `dispatch_tree` feature.
+    /// The concrete matching strategy (perfect hash, trie, or linear list) is
+    /// generated by `gen_program!` and selected by the `dispatch_phf` /
+    /// `dispatch_tree` / `dispatch_linear` features (mutually exclusive;
+    /// none = "auto", which picks the best strategy from the command table).
     ///
     /// # Errors
     ///