sameboy-0001: test_watchpoint() O(W) linear scan per GB memory read/write.
Every call to GB_read_memory / GB_write_memory scans all watchpoints when
n_watchpoints > 0. Fix: watchpoint_address_flags[0x10000] lookup table gives
O(1) early exit; 128x speedup at W=128.
sameboy-0002: should_break() O(B) linear scan per CPU instruction fetch.
GB_debugger_run() calls should_break() every instruction when debug_active.
Fix: breakpoint_address_set[0x10000] boolean table gives O(1) early exit;
128x speedup at B=128.
MOAD-0002: CLEAN, gb struct passed explicitly, no shared global state.
MOAD-0003: CLEAN, __thread only used for local string formatting buffers.
MOAD-0004: CLEAN, no network credentials logged.
MOAD-0005: CLEAN, no unsynchronized cache patterns found.
