feat(verify): save and replay fuzz corpora

Assisted-by: GLM 5.3 Flash

CHANGELOG.md

@@ -43,6 +43,11 @@ Unreleased changes on the `development` branch.
 - **`gasm verify --args`.**  Scalar arguments (`name=value`, decimal or
   `0x` hex) can now be supplied to a `--call` invocation alongside `--buf`
   buffers, closing the gap where only buffers could be supplied.
+- **Fuzz corpus save and replay.**  `gasm verify --fuzz --save-corpus dir`
+  records every input that crashes or mismatches as replayable JSON (buffer
+  contents and scalars, not raw pointers), and `gasm verify --replay dir`
+  re-runs the saved entries against the kernel in isolated child processes,
+  reporting whether each one reproduces.
 - **`gasm audit-instructions`.**  Black-box diff of a gasm encoder
   against the installed `go tool asm`, for amd64, arm64, riscv64 and
   loong64 (`gasm audit-instructions <arch>`): superset encodings