feat: system config DSL, services, CLI with rustc diagnostics

- System config parser (system/packages/services/boot/users blocks)
- Boot block: kernel, init, efi, swap, bootloader, root partition
- System-wide features, rollback config, swap partition
- Service block: per-init variants (runit, s6, etc.), system init selection via boot.init
- Feature-gated dependencies, config values accept numbers/bools/strings
- CLI: parse-package, parse-config, validate subcommands
- Rustc-style error diagnostics with source context, carets, help text
- Diagnostic module with ANSI color output

src/dsl/parser.cpp

@@ -209,6 +209,52 @@ void Parser::parse_body(PackageDef& pkg) {
             consume(TokenType::Rbrace);
             break;
 
+        case TokenType::KwService:
+            consume(TokenType::KwService);
+            consume(TokenType::Lbrace);
+            skip_newlines();
+            while (!at(TokenType::Rbrace) && !at(TokenType::Eof)) {
+                if (at(TokenType::Newline)) { advance(); continue; }
+                auto init_name = current_.lexeme;  // e.g. "runit", "s6"
+                advance();
+                consume(TokenType::Lbrace);
+                skip_newlines();
+                ServiceInit si;
+                while (!at(TokenType::Rbrace) && !at(TokenType::Eof)) {
+                    if (at(TokenType::Newline)) { advance(); continue; }
+                    auto key = current_.lexeme;
+                    advance();
+                    consume(TokenType::Equals);
+                    if (key == "exec") {
+                        si.exec = consume(TokenType::String).lexeme;
+                    } else if (key == "type") {
+                        si.type = consume(TokenType::String).lexeme;
+                    } else if (key == "user") {
+                        si.user = consume(TokenType::String).lexeme;
+                    } else if (key == "ports") {
+                        consume(TokenType::Lbracket);
+                        skip_newlines();
+                        while (!at(TokenType::Rbracket) && !at(TokenType::Eof)) {
+                            si.ports.push_back(
+                                std::stoi(std::string(current_.lexeme)));
+                            advance();
+                            skip_newlines();
+                            if (at(TokenType::Comma)) { consume(TokenType::Comma); }
+                            skip_newlines();
+                        }
+                        consume(TokenType::Rbracket);
+                    } else {
+                        si.env[key] = consume(TokenType::String).lexeme;
+                    }
+                    skip_newlines();
+                }
+                consume(TokenType::Rbrace);
+                pkg.service[std::string(init_name)] = std::move(si);
+                skip_newlines();
+            }
+            consume(TokenType::Rbrace);
+            break;
+
         case TokenType::KwPrepare:
             consume(TokenType::KwPrepare);
             pkg.prepare = parse_phase();