feat(debug): instruction-level coverage and FP register display

Assisted-by: GLM 5.3 Flash

docs/CLI.md

@@ -112,7 +112,7 @@ loong64). Requires a compiled binary on `$PATH` (not `go run`).
 | `--args <file>` | File containing the ABI0 argument block |
 | `--script <file>` | Run REPL commands from a file (one per line) and exit; `-` reads stdin |
 | `--timeout <dur>` | Kill the debuggee after this duration (e.g. `30s`); for headless `--script` runs |
-| `--cover` | Run to completion with breakpoints on every label and report which blocks executed |
+| `--cover` | Run to completion with a breakpoint on every instruction; report which executed, how often, and which labels were reached |
 
 REPL commands:
 
@@ -126,7 +126,7 @@ REPL commands:
 | `finish`, `fin` | Run until the function returns |
 | `continue`, `c` | Run until breakpoint, watchpoint or exit |
 | `disas [n]`, `u` | Disassemble n instructions at PC |
-| `regs` | Print general-purpose + YMM/XMM vector registers |
+| `regs` | Print general-purpose + vector/FP registers |
 | `where` | Show source line and nearest label at PC |
 | `stack` | Show stack near RSP (return address + ABI0 args) |
 | `bt`, `backtrace` | Backtrace (current frame + return address) |