Support base64 buffer dumps and complex hardware breakpoint reads

[anonymousException]

Support base64 buffer dumps

usage 1:
./stackplz_arm64 -n com.example.test -c tests/config_uprobe_test_base64.json
usage 2:
./stackplz_arm64 -n com.example.test --lib libtest.so --dumpbase64 -w testBytesBase64[buf:x1]
output:
with base64 :
[13173|13173|om.example.test] testBytesBase64(buf_bytes=0x7ff8c514e8 (base64:EgA0VngREhM=)) LR:0x731f123bc8 PC:0x731f123aa4 SP:0x7ff8c51430
without base64 :
[13268|13268|om.example.test] testBytesBase64(buf_bytes=0x7ff8c514e8(\x12\x004Vx\x11\x12\x13)) LR:0x731e066bc8 PC:0x731e066aa4 SP:0x7ff8c51430

[anonymousException]

Support complex hardware breakpoint reads

Summary

• Add --brk-point for hardware breakpoints.
• Reuse the existing uprobe-style complex argument expression parser for hardware breakpoint hits.
• Read args from sampled registers and /proc/<pid>/mem, then format them through the existing arg formatter.
• Keep dump parsing and RPC hardware breakpoint paths compatible with --brk-point.

Usage

Read simple registers when a hardware breakpoint hits:

./stackplz --pid <pid> \
  --brk <absolute_addr>:x \
  --brk-len 4 \
  --brk-point '[int:x0,uint64:x1]'

Read buffers through complex expressions:
./stackplz --pid <pid> \
  --brk <absolute_addr>:x \
  --brk-len 4 \
  --brk-point '[buf:4096:x0,buf:4096:x0+0x1000]' \
  --dumpbase64
Read through a pointer chain:
./stackplz --pid <pid> \
  --brk <absolute_addr>:x \
  --brk-len 4 \
  --brk-point '[*int:x0+0x18,buf:1000:x0+0x10.+0x20]' \
  --dumpbase64
Example output:
[pid|tid] event_addr:0x... hit_count:1 args(arg_0=..., arg_1=0x... (base64:...))
Notes
Unlike uprobe, this does not patch target instructions with BRK #5. Hardware breakpoint arg reads happen after perf sample delivery in userspace, so there is a small timing window.

[anonymousException]

Passed Auto built result:
stackplz_arm64