Add Lua SWIG bindings

[Copilot]

Adds Lua SWIG bindings for libcoraza, enabling Kong/OpenResty integrators to build a connector, following the same patterns as the Python and Java connectors.

coraza.i

• %typemap(argout) char **er: Add #elif defined(SWIGLUA) branch — SWIG Lua has no SWIG_Error; use lua_pushstring + SWIG_fail instead.
• #ifdef SWIGLUA block:
  • Byte-buffer typemap: collapses (const unsigned char *data, int length) → single Lua string via luaL_checklstring.
  • Callback trampolines: _swig_lua_error_trampoline / _swig_lua_debug_trampoline store Lua functions in the registry and invoke them synchronously (safe because Go's CGO runtime pins the goroutine to the calling OS thread).
  • %native wrappers for coraza_set_error_callback and coraza_set_debug_log_callback — note: %ignore must not precede %native in SWIG Lua or the function is silently dropped from the module table.

examples/lua/

• Makefile: swig -lua → coraza.so; pkg-config for Lua headers; Linux/macOS aware.
• simple_get.lua: 7 test cases — full transaction lifecycle, request body from file, WAF merge, error + debug callbacks, redirect intervention, WAF creation error, invalid input rejection.
• README.md: Prerequisites, build/run instructions, and a Kong/OpenResty usage snippet:

local coraza = require("coraza")
local cfg = coraza.coraza_new_waf_config()
coraza.coraza_rules_add(cfg, 'SecRule ...')
coraza.coraza_set_error_callback(cfg, function(rule_handle)
    ngx.log(ngx.WARN, coraza.coraza_matched_rule_get_error_log(rule_handle))
end)
local waf = coraza.coraza_new_waf(cfg)
coraza.coraza_free_waf_config(cfg)
-- per-request
local tx = coraza.coraza_new_transaction(waf)
-- ... process connection, URI, headers ...
local it = coraza.coraza_intervention(tx)
if it ~= nil then
    local status = it.status
    coraza.coraza_free_intervention(it)
    coraza.coraza_free_transaction(tx)
    ngx.exit(status)
end

CI

• New swig-lua job in swig.yml: ubuntu-latest + macos-latest × 2 Go versions; installs lua5.4/liblua5.4-dev (Linux) or lua via Homebrew (macOS).

[Hathoute]

So I'm already using this branch for APISIX, everything works.

However there's an issue with callbacks (debug and error) which SIGSEGV (happens frequently when configuring coraza using SecDebugLogLevel 9 and OWASP CRS. Not sure if this is specific to APISIX (my guess) since I've read your code and it seems correct.

[jptosso]

There are many improvements from upstream wasm project we should apply here, I will try to bring them

[Hathoute]

Maybe better in a new pull request after this one is merged (hopefully soon...)