docs: document watchpoint slot tracking and update debugger commands

README.md

@@ -251,16 +251,18 @@ portable Go implementation every kernel is derived from.
 ### Phase 4 — debugger · *done*
 
 - **`gasm debug`:** single-step a GAsm function, inspect registers (including
-  YMM vector registers), set breakpoints on labels, allocate and fill named
-  buffers, and hex-dump memory — the interactive counterpart to Phase 3's
-  execution substrate.
-  - **MVP** — *done.*  ptrace-based debuggee subprocess (PTRACE_TRACEME +
-    LockOSThread), entry breakpoint (auto-run to function start),
-    single-step, register inspection (GPR + YMM/XMM via PTRACE_GETFPREGS),
-    label resolution, breakpoint management via `/proc/pid/mem`, named
-    buffer allocation with pattern filling (`--buf`), and an interactive REPL.
-  - **Remaining:** disassembly at PC (x86asm decode), memory-write support,
-    watchpoints, and source-line mapping.
+  YMM vector registers), set breakpoints and watchpoints on addresses, write
+  memory, allocate and fill named buffers, disassemble at PC, and trace the
+  source-line mapping — the interactive counterpart to Phase 3's execution
+  substrate.
+  - ptrace-based debuggee subprocess (PTRACE_TRACEME + LockOSThread), entry
+    breakpoint (auto-run to function start), single-step, register inspection
+    (GPR + YMM/XMM via PTRACE_GETFPREGS), label resolution, breakpoint
+    management via `/proc/pid/mem`, named buffer allocation with pattern
+    filling (`--buf`), interactive REPL with conditional breakpoints, four
+    hardware watchpoints (DR0–DR3), step-over-CALL, run-to-return, backtrace,
+    memory read/write, disassembly at PC (x86asm), and source-line ↔ offset
+    mapping.
 
 ### Phase 5 — the other architectures · *in progress*