feat(game): preview all mission roots by default

apps/fparkan-game/src/main.rs

@@ -1012,7 +1012,11 @@ impl Args {
         let mut frames = 1;
         let mut backend = RenderBackendMode::Planning;
         let mut load_progress = None;
-        let mut preview_roots = NonZeroUsize::MIN;
+        // A native static-Vulkan invocation is the usable mission preview, so
+        // its default scope covers every root. `PreviewRoots` is clamped by the
+        // runtime to the decoded mission length; an explicit --preview-roots N
+        // remains available for bounded diagnostic work.
+        let mut preview_roots = NonZeroUsize::MAX;
         let mut legacy_camera_capture = None;
         let mut iter = args.iter();
         while let Some(arg) = iter.next() {
@@ -1224,7 +1228,7 @@ mod tests {
                 frames: 3,
                 backend: RenderBackendMode::Planning,
                 load_progress: None,
-                preview_roots: NonZeroUsize::MIN,
+                preview_roots: NonZeroUsize::MAX,
                 legacy_camera_capture: None,
             })
         );
@@ -1247,7 +1251,7 @@ mod tests {
                 frames: 1,
                 backend: RenderBackendMode::StaticVulkan,
                 load_progress: None,
-                preview_roots: NonZeroUsize::MIN,
+                preview_roots: NonZeroUsize::MAX,
                 legacy_camera_capture: None,
             })
         );
@@ -1305,7 +1309,7 @@ mod tests {
                 frames: 1,
                 backend: RenderBackendMode::Planning,
                 load_progress: Some(PathBuf::from("target/probe.txt")),
-                preview_roots: NonZeroUsize::MIN,
+                preview_roots: NonZeroUsize::MAX,
                 legacy_camera_capture: None,
             })
         );

docs/tomes/05-render.md

@@ -972,11 +972,12 @@ of the first-root static-preview bridge, not a claim that the two games' full
 mission renderers are compatible.
 
 The preview now has an explicit root-prefix contract. `--preview-roots N`
-prepares the first non-zero `N` TMA roots for the opt-in static Vulkan path;
-the default remains one root. Normal mission loading remains full and
-transactional, so this is not a hidden relaxation of gameplay validation. The
-previous all-root probe timed out at `Graph`; the prefix makes broader scene
-work measurable without pretending that a bounded preview is the full game.
+prepares the first non-zero `N` TMA roots for the opt-in static Vulkan path.
+Without that diagnostic limiter, the static Vulkan path now requests every TMA
+root (the runtime clamps the request to the decoded mission length), so a
+normal native preview no longer silently displays just root zero. Normal mission
+loading remains full and transactional; the prefix is retained for bounded
+investigation rather than as a hidden relaxation of gameplay validation.
 
 ### Shared terrain/root diagnostic frame