feat: eval/exec of strings, gallery Replay, callable actions; iNSight and SomethingBetter now pass

- pyparse.ts: parser for expressions and simple statements built at run time, producing
  the sandbox's own IR; backs eval() and exec() (e.g. exec("persistent." + var + " = 0"))
- Replay/EndReplay and renpy.end_replay: the engine stashes the full game state, runs the
  label with the given scope and restores everything when it ends; locked replays are
  insensitive. Save loading shared as applySave()
- Screen actions are callable (MainMenu(confirm=False)())
- jump main_menu_screen is Ren'Py's own label: it opens the player's main menu
- Screens: a closing quote ends the word before a letter ("text"size 15) but not before
  an operator ("a"+b); Text(...) pictures in image blocks
- README: current capabilities and limits of the Ren'Py support

Strict compatibility check on the local collection: Tomie, Twisted-Thoughts, Hooked,
iNSight-of-you and SomethingBetter pass; TheFixer (custom AlphaMask wardrobe, missing
labels) and That_New_Teacher (custom statements, Render API) do not.

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

frontend/src/player/engine.ts

@@ -8,6 +8,7 @@ import { languageName, rememberLanguage, type Translator } from "./i18n";
 import { naniText } from "./naninovel";
 import { ScreenManager, type ScreenHost } from "./screens";
 import { pythonModules } from "./pymodules";
+import { parseExpression, parseStatements } from "./pyparse";
 import { DEFAULT_SETTINGS, SLOTS, Restart, el, loadJSON, saveJSON, type SaveApi, type SaveMeta, type Settings } from "./engine-util";
 import type {
   CharacterDef, Expr, Frame, GameData, ImageDef, Label, Layer, Manifest, Node, SaveData, ScriptModule,
@@ -39,6 +40,7 @@ export class Engine {
   private waiters: (() => void)[] = [];
   private screens: ScreenManager;
   private screenFonts = new Map<string, string>();
+  private replayStash: SaveData | null = null;
   private seenImages = new Set<string>();
   private running = false;
 
@@ -344,7 +346,10 @@ export class Engine {
       version: () => "pgvn",
       ...this.screens.renpyApi(),
       // presentation-only: nothing to roll back or replay, and the next transition is chosen by `with`
-      end_replay: () => null,
+      end_replay: () => {
+        this.endReplay();
+        return null;
+      },
       partial: (f: any, ...bound: any[]) => (...args: any[]) => f(...bound, ...args),
       loadable: (path: any) => this.fileUrl(String(path)) !== null,
       is_init_phase: () => false,
@@ -391,6 +396,13 @@ export class Engine {
       // a read-only view: `"name" in globals()` works, writes do not reach the game
       globals: () => new PyDict(Object.entries(this.store)),
       print: () => null,
+      // code built at run time ("persistent." + name + " = 0") goes through a parser producing the same
+      // sandboxed IR; there is no other way to run source text
+      eval: (source: any) => this.py.eval(parseExpression(pyStr(source))),
+      exec: (source: any) => {
+        this.py.exec(parseStatements(pyStr(source)));
+        return null;
+      },
       Borders: (...a: number[]) => a,
       ...pythonModules(),
       _window_hide: () => { this.windowShown = false; this.textbox.classList.add("pg-hidden"); return null; },
@@ -614,6 +626,8 @@ export class Engine {
         if (/^https?:\/\//i.test(url)) window.open(url, "_blank", "noopener,noreferrer");
       },
       setLanguage: (code) => void this.setLanguage(code ?? this.game.sourceLang ?? "und"),
+      startReplay: (label, scope) => this.startReplay(label, scope),
+      endReplay: () => this.endReplay(),
       quickSave: () => void this.save("quick"),
       quickLoad: () => void this.load("quick"),
       transform: (name) => this.game.transforms[name] ?? null,
@@ -726,6 +740,7 @@ export class Engine {
   }
 
   private jump(target: string, args?: { a: any[]; kw: Record<string, any> }, frame?: Frame) {
+    if (target === "main_menu_screen" || target === "_main_menu_screen") target = "__main_menu__";
     if (target === "__main_menu__" || target === "__quit__") {
       throw new Restart(target);
     }
@@ -776,6 +791,10 @@ export class Engine {
   private doReturn() {
     const frame = this.stack.pop();
     if (!frame) {
+      if (this.replayStash) {
+        this.endReplay(); // the replayed label ran out: back to the game
+        return;
+      }
       this.cur = { label: "", path: [0] };
       return;
     }
@@ -1459,27 +1478,54 @@ export class Engine {
       frames.forEach((f, i) => Object.assign(f, mapped[i]));
     }
     if (!data.revision && !(await this.confirmAsk("Старое сохранение не содержит ревизию игры. После изменения скрипта его позиции могут быть неверны. Попробовать загрузить?", "Загрузить"))) return;
+    this.replayStash = null;
+    this.restart(() => this.applySave(data));
+  }
+
+  /** Put the game into the state described by a save (also used to come back from a replay). */
+  private applySave(data: SaveData) {
+    this.resetStore();
+    Object.assign(this.store, decodeValue(data.store));
+    this.screens.restore(decodeValue(data.screens ?? []));
+    this.renderer.scene();
+    for (const s of data.scene) {
+      const img = this.resolveImage(s.name);
+      if (img) this.renderer.show(img, s.tag, s.at, { zorder: s.zorder });
+    }
+    this.renderer.commit();
+    this.audio.stopAll();
+    if (data.music) this.audio.play("music", [data.music.file], { loop: data.music.loop, fadein: 0.5 });
+    this.windowShown = data.window;
+    this.renderer.camera(data.camera ?? []);
+    this.stack = data.stack.map((f) => ({ ...f, saved: decodeValue(f.saved) }));
+    this.cur = data.cur;
+    this.lastSay = null;
+    this.history = [];
+  }
+
+  /** Gallery replay: run a label with the given variables, then return to exactly where the game was. */
+  private startReplay(label: string, scope: Record<string, any> | null) {
+    if (!this.labels.has(label)) {
+      this.notify(`Метка «${label}» не найдена`);
+      return;
+    }
+    if (!this.replayStash) this.replayStash = this.snapshotState();
     this.restart(() => {
-      this.resetStore();
-      Object.assign(this.store, decodeValue(data.store));
-      this.screens.restore(decodeValue(data.screens ?? []));
-      this.renderer.scene();
-      for (const s of data.scene) {
-        const img = this.resolveImage(s.name);
-        if (img) this.renderer.show(img, s.tag, s.at, { zorder: s.zorder });
-      }
-      this.renderer.commit();
-      this.audio.stopAll();
-      if (data.music) this.audio.play("music", [data.music.file], { loop: data.music.loop, fadein: 0.5 });
-      this.windowShown = data.window;
-      this.renderer.camera(data.camera ?? []);
-      this.stack = data.stack.map((f) => ({ ...f, saved: decodeValue(f.saved) }));
-      this.cur = data.cur;
-      this.lastSay = null;
-      this.history = [];
+      for (const [key, value] of Object.entries(scope ?? {})) this.store[key] = value;
+      this.store._in_replay = label;
+      this.stack = [];
+      this.cur = { label: "", path: [0] };
+      this.guardedJump(label);
     });
   }
 
+  private endReplay() {
+    const stash = this.replayStash;
+    if (!stash) return;
+    this.replayStash = null;
+    this.restart(() => this.applySave(stash));
+  }
+
   private setSkip(on: boolean) {
     this.skip = on;
     this.renderer.fast = on;