Add headless parallel eu7v2 scenario bake with streaming and PLCE placements

Enable --eu7v2-bake from the main binary: parallel module pool, bounded-RAM
spool flush, streaming terrain triangles, flat include/model parsing, and
eu7v2 emit/load with optional verify. Large placement .scm files emit lean
PLCE records and bake referenced .inc modules separately for reuse.

- CLI: --eu7v2-bake, --eu7v2-verify, --eu7v2-mem-limit-gb, --eu7v2-threads,
  --eu7v2-max-parse; wire max_threads through to the bake parser
- eu7v2 v2 records: PLCE placements, runtime emitter/loader, batch verify
- Parallel bake pool with session cache; drop heavy-serial parse gate in spool
  mode; parse concurrency matches thread count
- Streaming terrain: batched parallel parse+bake, scan/bake pipeline, shape
  spool with persistent buffered I/O and flush-before-read
- Parallel flat-file streaming for models/includes; pack/model spool for
  low-memory incremental flush
- Optional 50 GB private-bytes guard during headless bake

Braniewo_szeroki: 160 modules, verify PASS, ~34s bake (nmt100 ~17s vs ~190s
serial baseline).

Co-authored-by: Cursor <cursoragent@cursor.com>

scene/eu7/eu7_bake.cpp

@@ -32,6 +32,8 @@ http://mozilla.org/MPL/2.0/.
 
 
 
+#include <algorithm>
+
 #include <thread>
 
 
@@ -62,7 +64,31 @@ bake_thread_count() {
 
     auto const hardware { std::thread::hardware_concurrency() };
 
-    return hardware > 0 ? hardware : 1u;
+    if( hardware == 0 ) {
+
+        return 1u;
+
+    }
+
+    int percent { Global.eu7_bake_cpu_percent };
+
+    if( percent < 1 ) { percent = 1; }
+
+    if( percent > 100 ) { percent = 100; }
+
+    unsigned const threads {
+
+        std::max( 1u,
+
+            static_cast<unsigned>( ( static_cast<unsigned long long>( hardware ) * percent + 50 ) / 100 ) ) };
+
+    WriteLog(
+
+        "EU7 bake: auto watki=" + std::to_string( threads ) +
+
+        " (" + std::to_string( percent ) + "% z " + std::to_string( hardware ) + " rdzeni logicznych)" );
+
+    return threads;
 
 }
 
@@ -90,7 +116,27 @@ run_scenario_tree_bake(
 
     std::string error;
 
-    if( false == bake_parser::bake_scenario_tree( text_root, bake_thread_count(), error ) ) {
+    bool bake_ok { false };
+
+    if( Global.eu7v2_runtime ) {
+
+        auto const report {
+
+            bake_parser::bake_scenario_tree_eu7v2( text_root, bake_thread_count(), false ) };
+
+        bake_ok = report.baked;
+
+        error = report.error;
+
+    }
+
+    else {
+
+        bake_ok = bake_parser::bake_scenario_tree( text_root, bake_thread_count(), error );
+
+    }
+
+    if( false == bake_ok ) {
 
         if( probe_file( eu7_path ) ) {