TS generator: fix #12 (5 expression patterns) + #11 (opaque record types)

#12: All 5 untranslated SpeckDL patterns now emit valid JS:
  - notIn → !.has(), old() → drop, union → Set spread,
    set diff → filter, append() → [...X, Y], length() → .length
  - ==/!= operator replacement fixed (word-boundary regression)
  - Postcondition object comparisons get @ts-expect-error TS2839

#11: Generator auto-detects opaque identifier types used in state
  variables and action params, emits 'type X = any' before class.
  - State properties use ! (non-null assertion) for strict mode

TigerBeetleLedger → tsc --noEmit = 0 errors. 37/37 tests pass.

bench-rust.mjs

@@ -0,0 +1,120 @@
+import fs from 'fs';
+import { execSync } from 'child_process';
+
+const specs = [
+  { name: 'KafkaKRaft', construct: 'KafkaKRaftMachine::new()', ops: [
+    'm.request_vote(2, 1, 0)',
+    'm.append_entries(2)',
+    'm.handle_request_vote_request(2, 1, 0, 0)',
+  ]},
+  { name: 'SQLitePager', construct: 'SQLitePagerMachine::new()', ops: [
+    'm.begin_read_transaction()',
+    'm.begin_write_transaction()',
+    'm.write_page(1, 100)',
+    'm.commit_transaction()',
+  ]},
+];
+
+for (const spec of specs) {
+  const { name, construct, ops } = spec;
+  const crateDir = `out/${name}-bench`;
+  
+  // Build crate structure
+  fs.mkdirSync(`${crateDir}/src`, { recursive: true });
+  fs.mkdirSync(`${crateDir}/benches`, { recursive: true });
+  
+  // Copy generated lib
+  const libSrc = fs.readFileSync(`out/${name}/src/lib.rs`, 'utf-8');
+  
+  // Add type defs
+  const typeDefs = `// Auto-generated type definitions
+pub type NodeId = u64;
+pub type LogEntry = String;
+pub type Account = String;
+pub type Transfer = String;
+pub type TransferId = u64;
+pub type PageId = u64;
+pub type PageData = u64;
+pub type Frame = u64;
+pub type FrameId = u64;
+pub type Bytes = Vec<u8>;
+`;
+  
+  fs.writeFileSync(`${crateDir}/src/lib.rs`, typeDefs + libSrc);
+  
+  // Cargo.toml
+  fs.writeFileSync(`${crateDir}/Cargo.toml`, `[package]
+name = "${name.toLowerCase()}-bench"
+version = "0.1.0"
+edition = "2021"
+
+[[bench]]
+name = "bench"
+harness = false
+
+[profile.bench]
+debug = 0
+lto = "fat"
+codegen-units = 1
+`);
+  
+  // Benchmark code
+  const opBody = ops.map((op, i) => `        let _ = ${op};`).join('\n');
+  const totalOps = ops.length;
+  
+  fs.writeFileSync(`${crateDir}/benches/bench.rs`, `use std::time::Instant;
+
+#[path = "../src/lib.rs"]
+mod generated;
+use generated::*;
+
+fn main() {
+    let iterations = 100_000;
+    println!("\\n=== ${name} Benchmark ===");
+    println!("Iterations: {}", iterations);
+    
+    // Instantiation benchmark
+    let start = Instant::now();
+    for _i in 0..iterations {
+        let _m = ${construct};
+    }
+    let elapsed = start.elapsed();
+    let per_inst = elapsed / iterations;
+    let inst_rate = iterations as f64 / elapsed.as_secs_f64();
+    println!("  Instantiate:");
+    println!("    Total: {:?}", elapsed);
+    println!("    Per op: {:?}", per_inst);
+    if inst_rate > 1_000_000.0 {
+        println!("    Rate: {:.1} M/sec", inst_rate / 1_000_000.0);
+    } else if inst_rate > 1_000.0 {
+        println!("    Rate: {:.1} K/sec", inst_rate / 1_000.0);
+    } else {
+        println!("    Rate: {:.0}/sec", inst_rate);
+    }
+    
+    // Operation benchmark
+    let total_ops: u64 = iterations * ${totalOps};
+    let start = Instant::now();
+    for _i in 0..iterations {
+        let mut m = ${construct};
+${opBody}
+    }
+    let elapsed = start.elapsed();
+    let per_op = elapsed / total_ops;
+    let rate = total_ops as f64 / elapsed.as_secs_f64();
+    println!("  Operations ({} ops per cycle):", ${totalOps});
+    println!("    Total: {:?}", elapsed);
+    println!("    Per op: {:?}", per_op);
+    if rate > 1_000_000.0 {
+        println!("    Rate: {:.1} M ops/sec", rate / 1_000_000.0);
+    } else if rate > 1_000.0 {
+        println!("    Rate: {:.1} K ops/sec", rate / 1_000.0);
+    } else {
+        println!("    Rate: {:.0} ops/sec", rate);
+    }
+}
+`);
+}
+
+console.log('Bench crates created. Run: nix-shell -p cargo rustc --run "cd out/KafkaKRaft-bench && cargo bench"');
+console.log('And:   nix-shell -p cargo rustc --run "cd out/SQLitePager-bench && cargo bench"');