feat(verify): add --call and --buf flags for single-function invocation

Assisted-by: GLM 5.2

CHANGELOG.md

@@ -14,6 +14,20 @@ Unreleased changes on the `development` branch.
 - **`gasm diff --map`** — compare functions whose names differ between files
   (e.g. `--map wideCopyAVX2=wideCopyAVX512` pairs AVX2 and AVX-512 variants
   regardless of suffix). Unmapped functions fall back to the original name match.
+- **`gasm verify --call`** — invoke a single function with user-supplied buffers
+  (`--buf name:size:pattern`) instead of the smoke/abi/fuzz sweeps. Patterns:
+  `zero`, `ones`, `seq`, or a hex blob. Useful for partial functions (e.g.
+  decoders) that crash on random input but should succeed on valid data.
+  The arg block is printed before and after the call, showing return values.
+- **`gasm verify --ground-truth`** now documented in `--help` (was already a flag,
+  just missing from the help text).
+
+### Fixed
+
+- **Signature parser** — grouped Go parameters like `dst, src []byte` are now
+  parsed correctly (both get type `[]byte`). Previously the first name was
+  treated as its own type (`dst` with size 8), causing wrong ABI0 arg-block
+  layout in both `verify --call` and the fuzzer.
 
 ## [0.29.0] — 2026-08-05