P0: Global-variable CRUD + full function signatures for the decompiler CLI

[mahaloz]

What & why

IDALib can list/read/rename/type globals and set complete function signatures; the DecLib CLI could do neither. This adds both.

Globals — decompiler global list|get|rename|retype

• IDA enumeration broadened: was a hardcoded scan of .artifacts/.bss only; now uses idautils.Names(), so named data across .data/.bss/.rodata/.got all surface (function starts and code labels filtered out).
• Ghidra retype implemented (DataUtilities.createData) — previously a # TODO: pass. Also filtered Ghidra's enumeration to memory-mapped symbols, so synthetic/EXTERNAL symbols (which lift to negative addresses and can't round-trip) no longer pollute global list.
• Base get_global_var (direct read, no cache) + client proxy.

$ decompiler global list --filter 'key|flag'
ADDR         SIZE   TYPE                 NAME
0x4040       8      char *               g_key
$ decompiler global rename 0x4040 g_secret_key
$ decompiler global retype 0x4040 "char[32]"

Signatures — decompiler signature get|set

• Shared declib/api/prototype.py parses/formats C prototypes (pointer returns/args, varargs, void).
• IDA applies the whole prototype atomically via idc.SetType. This sidesteps a real bug in the existing set_function_header: when both return type and args change, the args pass rebuilds the prototype from a stale cfunc and clobbers the just-applied return type. SetType sets it in one shot (and can change the parameter count).
• Ghidra/Binary Ninja use the generic parse → header-overwrite → set path (their setters apply return + arg types independently). angr sets arg names but not types.

$ decompiler signature get main
int main(int argc, char **argv)
$ decompiler signature set main "int main(int argc, char **argv, char **envp)"
$ decompiler signature get main
int main(int argc, char **argv, char **envp)

Tests

Backend-parametrized: test_global_list, test_global_rename, test_signature_get, test_signature_set, test_signature_get_missing_exits_nonzero, plus backend-free TestPrototypeParser.

• IDA: full pass. Ghidra: full pass. angr: signature get/missing pass; globals + signature-type-set skip (unsupported, gated by capability flags).

Support matrix

	IDA	Ghidra	Binary Ninja	angr
global list/get/rename	✅	✅	✅	—
global retype	✅	✅ (new)	✅	—
signature get	✅	✅	✅	✅
signature set (types)	✅ (atomic)	✅	✅	names only

---

Third PR in the IDALib-parity series. Based on feat/cli-comments (#205).

🤖 Generated with Claude Code

https://claude.ai/code/session_01HfZHdprXg38re1XyKxzGg5

[mahaloz]

Integrated into main as commit 0ea35a5. The stack got tangled when the bottom PRs (#204/#205) were squash-merged (#205 landed on feat/cli-persistence instead of main), so I reconciled by cherry-picking the whole series onto main linearly. The exact reviewed content of this PR is on main — closing this stacked PR as its changes are shipped.