fix: resolve audit findings — stale text, dead code, build tags, docs

Assisted-by: MiMo V2.5 Pro

docs/ARCHITECTURE.md

@@ -97,10 +97,11 @@ fixed-arity instructions (`RET`, `NOP`, `JMP`, `CALL`) carry counts at all.
 
 Rules are conservative by design — silence beats a false positive.  The rules
 are `unknown-instruction`, `operand-count`, `undefined-label`,
-`duplicate-label`, `missing-ret`, `missing-textflag-include`, `abi-argsize` and
-`unreachable-code`.  Every diagnostic carries a stable code so callers can
-disable rules individually, and arch-specific rules switch off entirely when
-the target architecture cannot be inferred from the file name.
+`duplicate-label`, `missing-ret`, `missing-textflag-include`, `abi-argsize`,
+`unreachable-code`, `register-clobber`, `funcdata-pcdata`, `unused-label`,
+`invalid-textflag` and `stack-imbalance`.  Every diagnostic carries a stable
+code so callers can disable rules individually, and arch-specific rules switch
+off entirely when the target architecture cannot be inferred from the file name.
 
 Two things keep the rules honest on real-world code:
 
@@ -365,7 +366,7 @@ masked), reporting any encoding drift.
 
 ### `debug`
 
-The interactive debugger (Phase 4, linux/amd64).  It launches the target
+The interactive debugger (all four architectures).  It launches the target
 function in a child process that maps the JIT code, calls
 `PTRACE_TRACEME`, and stops; the parent attaches via ptrace and controls
 execution.  Breakpoints are patched as INT3 bytes through `/proc/pid/mem`

docs/CLI.md

@@ -52,7 +52,7 @@ Rules: `unknown-instruction`, `operand-count`, `undefined-label`,
 
 ## `gasm asm [--format raw|elf|goobj] [-p pkg] [-o out] <file>`
 
-Assemble FILE (amd64) to machine code.
+Assemble FILE to machine code (amd64, arm64, riscv64, loong64).
 
 | Flag | Description |
 |------|-------------|
@@ -90,7 +90,7 @@ return values and any output written to the buffers.
 
 ## `gasm debug --func <name> [--buf spec] <file.s>`
 
-Interactive debugger for JIT-assembled amd64 functions. Requires a
+Interactive debugger for JIT-assembled functions (amd64, arm64, riscv64, loong64). Requires a
 compiled binary on `$PATH` (not `go run`).
 
 | Flag | Description |

docs/DEVELOPMENT.md

@@ -101,7 +101,7 @@ format/             Canonical formatter
 lsp/                Language Server Protocol server
 asm/                Standalone assembler, encoder, object emitters
 verify/             JIT execution, differential testing, ABI checks
-debug/              Interactive ptrace debugger (linux/amd64)
+debug/              Interactive ptrace debugger (all four architectures)
 _gen/               Instruction table generator
 testdata/           Test fixtures
 docs/               Architecture, development, CLI reference