feat(asm): emit GOOBJ objects that link directly with the Go toolchain

Assisted-by: Qwen 3.8 Max Preview

docs/ARCHITECTURE.md

@@ -250,10 +250,19 @@ and Mach-O writers (`gasm asm --format elf|macho`) lay the code and data out
 as `.text`/`.data` (or `__text`/`__data`) sections, export a symbol per
 `TEXT` and `GLOBL` (the `<>` ones local, the rest global) and emit one
 PC-relative relocation per static-symbol reference — undefined external
-symbols included, so the output links with the system toolchain.  GOOBJ
-emission, the format the Go linker consumes directly, is the remaining
-piece of Phase 2 (together with the rest of the EVEX set and the other
-architectures).
+symbols included, so the output links with the system toolchain.  The GOOBJ
+emitter (`gasm asm --format goobj`) writes the format the Go linker consumes
+directly: the functions as non-package symbols (the way `cmd/asm` records
+assembly symbols), the `GLOBL` data, one `FuncInfo` per function and the
+pc-value tables — `pcsp` built from the prologue and epilogue stack
+boundaries, plus flat `pcfile`, `pcline` and `pcinline` tables — so a
+gasm-assembled object drops into a `go build` in place of the toolchain's.
+The object preamble (the version-and-experiment header the linker compares
+verbatim) is captured from the installed `go tool asm`, so the output is
+always consistent with the toolchain that links it.  External cross-package
+references and the implicit funcdata/DWARF symbols remain future work (the
+linker fills the latter's defaults); the rest of Phase 2 is those, the
+remaining EVEX forms and the other architectures.
 
 ## Extension points