feat: add lang-mcp cartridge for nextgen-languages

New cartridge supporting all 12 hyperpolymath nextgen-languages:
Eclexia, AffineScript, BetLang, Ephapax, MyLang, WokeLang,
Anvomidav, Phronesis, Error-lang, Julia-the-Viper, Me-dialect, Oblibeny.

Architecture: session-based state machine (idle → compiling → checked →
evaluating → idle/error) with 8 concurrent sessions, URL-based language
service dispatch, type-checking and evaluation endpoints.

Zig FFI: 6 exported functions + 6 tests. V-lang adapter: full CRUD +
typecheck + eval. MCP bridge updated with lang-mcp in Teranga menu.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: hyperpolymath

cartridges/lang-mcp/adapter/lang_adapter.v

@@ -0,0 +1,183 @@
+// SPDX-License-Identifier: PMPL-1.0-or-later
+// Copyright (c) 2026 Jonathan D.A. Jewell (hyperpolymath) <j.d.a.jewell@open.ac.uk>
+//
+// Lang-MCP Cartridge — V-lang adapter layer.
+//
+// Bridges the Zig FFI (lang_ffi.zig) to REST/gRPC/GraphQL endpoints.
+// Provides language session management, type-checking, and evaluation
+// for the hyperpolymath nextgen-languages family.
+
+module lang_adapter
+
+import json
+
+// ═══════════════════════════════════════════════════════════════════════
+// C FFI declarations (link against lang_ffi built from Zig)
+// ═══════════════════════════════════════════════════════════════════════
+
+fn C.lang_session_start(lang_id int, name_ptr &u8, name_len usize) int
+fn C.lang_session_set_url(sess_idx int, url_ptr &u8, url_len usize) int
+fn C.lang_session_end(sess_idx int) int
+fn C.lang_session_state(sess_idx int) int
+fn C.lang_session_language(sess_idx int) int
+fn C.lang_typecheck(sess_idx int, src_ptr &u8, src_len usize, out_ptr &u8, out_len usize) int
+fn C.lang_eval(sess_idx int, src_ptr &u8, src_len usize, out_ptr &u8, out_len usize) int
+fn C.lang_reset()
+
+// ═══════════════════════════════════════════════════════════════════════
+// Types
+// ═══════════════════════════════════════════════════════════════════════
+
+enum LangState {
+	idle = 0
+	compiling = 1
+	checked = 2
+	evaluating = 3
+	err = 4
+}
+
+enum Language {
+	eclexia = 1
+	affinescript = 2
+	betlang = 3
+	ephapax = 4
+	mylang = 5
+	wokelang = 6
+	anvomidav = 7
+	phronesis = 8
+	error_lang = 9
+	julia_the_viper = 10
+	me_dialect = 11
+	oblibeny = 12
+	custom = 99
+}
+
+fn state_label(s int) string {
+	return match s {
+		0 { 'idle' }
+		1 { 'compiling' }
+		2 { 'checked' }
+		3 { 'evaluating' }
+		4 { 'error' }
+		else { 'unknown' }
+	}
+}
+
+fn language_label(lang string) !int {
+	return match lang {
+		'eclexia' { 1 }
+		'affinescript' { 2 }
+		'betlang' { 3 }
+		'ephapax' { 4 }
+		'mylang' { 5 }
+		'wokelang' { 6 }
+		'anvomidav' { 7 }
+		'phronesis' { 8 }
+		'error-lang' { 9 }
+		'julia-the-viper' { 10 }
+		'me-dialect' { 11 }
+		'oblibeny' { 12 }
+		else { return error('unknown language: ${lang}') }
+	}
+}
+
+// ═══════════════════════════════════════════════════════════════════════
+// REST API Responses
+// ═══════════════════════════════════════════════════════════════════════
+
+struct SessionResponse {
+	session  int
+	language string
+	state    string
+}
+
+// ═══════════════════════════════════════════════════════════════════════
+// Adapter Functions (called by main adapter router)
+// ═══════════════════════════════════════════════════════════════════════
+
+pub fn start_session(language_name string, session_name string) !SessionResponse {
+	lang_id := language_label(language_name)!
+	sess := C.lang_session_start(lang_id, session_name.str, usize(session_name.len))
+	if sess < 0 {
+		return match sess {
+			-1 { error('no session slots available (max 8)') }
+			-2 { error('invalid session name') }
+			else { error('unknown error (code ${sess})') }
+		}
+	}
+	return SessionResponse{
+		session: sess
+		language: language_name
+		state: 'idle'
+	}
+}
+
+pub fn set_url(session int, url string) !string {
+	result := C.lang_session_set_url(session, url.str, usize(url.len))
+	return match result {
+		0 { 'URL set for session ${session}' }
+		-1 { return error('invalid or inactive session') }
+		-6 { return error('URL empty or too long') }
+		else { return error('unknown error (code ${result})') }
+	}
+}
+
+pub fn end_session(session int) !string {
+	result := C.lang_session_end(session)
+	return match result {
+		0 { 'session ${session} ended' }
+		-1 { return error('invalid or inactive session') }
+		else { return error('unknown error (code ${result})') }
+	}
+}
+
+pub fn get_state(session int) string {
+	s := C.lang_session_state(session)
+	return state_label(s)
+}
+
+pub fn typecheck(session int, source string) !string {
+	if session < 0 || session > 7 {
+		return error('invalid session index: ${session}')
+	}
+	mut out_buf := []u8{len: 65536}
+	result := C.lang_typecheck(session, source.str, usize(source.len), out_buf.data, usize(out_buf.len))
+	if result < 0 {
+		return match result {
+			-1 { error('invalid or inactive session') }
+			-2 { error('session not in valid state for type-checking') }
+			-5 { error('output buffer too small') }
+			-6 { error('no service URL set for this session') }
+			-7 { error('type-check service call failed') }
+			else { error('unknown error (code ${result})') }
+		}
+	}
+	return out_buf[..result].bytestr()
+}
+
+pub fn evaluate(session int, source string) !string {
+	if session < 0 || session > 7 {
+		return error('invalid session index: ${session}')
+	}
+	mut out_buf := []u8{len: 65536}
+	result := C.lang_eval(session, source.str, usize(source.len), out_buf.data, usize(out_buf.len))
+	if result < 0 {
+		return match result {
+			-1 { error('invalid or inactive session') }
+			-2 { error('session not in valid state for evaluation') }
+			-5 { error('output buffer too small') }
+			-6 { error('no service URL set for this session') }
+			-7 { error('evaluation service call failed') }
+			else { error('unknown error (code ${result})') }
+		}
+	}
+	return out_buf[..result].bytestr()
+}
+
+pub fn list_languages() string {
+	return '["eclexia","affinescript","betlang","ephapax","mylang","wokelang","anvomidav","phronesis","error-lang","julia-the-viper","me-dialect","oblibeny"]'
+}
+
+pub fn reset() {
+	C.lang_reset()
+}