fix(web): clean up wasm32 build warnings and wire /play route to Bevy canvas

- solitaire_data/sync_client.rs: fix SyncPayload/SyncResponse import split
  (SyncResponse is needed by LocalOnlyProvider which compiles on wasm32)
- solitaire_engine/assets/sources.rs: cfg-gate AssetApp/AssetSourceBuilder
  imports (only used in the non-wasm FileAssetReader block)
- solitaire_engine/auto_complete_plugin.rs: cfg-gate AUTO_COMPLETE_CHIME_VOLUME
- solitaire_engine/daily_challenge_plugin.rs: cfg-gate Task/AsyncComputeTaskPool
  imports and DailyChallengeTask struct (server fetch systems are non-wasm only)
- solitaire_engine/resources.rs: cfg-gate std::sync::Arc (TokioRuntimeResource
  is non-wasm only)
- solitaire_engine/settings_plugin.rs: cfg-gate ScanThemes variant, pill_button,
  and their match arms; fix refresh_registry import placement
- solitaire_server/src/lib.rs: point /play route at play.html (Bevy canvas);
  keep /play-classic serving game.html during transition period
- build_wasm.sh: add --no-typescript to wasm-bindgen call for canvas build
- solitaire_server/web/pkg: add canvas.js + canvas_bg.wasm build artifacts

wasm32 build and native clippy --workspace -D warnings both clean.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

solitaire_engine/src/settings_plugin.rs

@@ -33,9 +33,9 @@ use crate::events::{
 use crate::font_plugin::FontResource;
 use crate::progress_plugin::ProgressResource;
 use crate::resources::{SettingsScrollPos, SyncStatus, SyncStatusResource};
-use crate::theme::{ThemeThumbnailCache, ThemeThumbnailPair, refresh_registry};
+use crate::theme::{ThemeThumbnailCache, ThemeThumbnailPair};
 #[cfg(not(target_arch = "wasm32"))]
-use crate::theme::{ImportError, import_theme};
+use crate::theme::{ImportError, import_theme, refresh_registry};
 use crate::ui_focus::{FocusGroup, FocusRow, Focusable, FocusedButton};
 use crate::ui_modal::{
     ButtonVariant, ModalButton, ModalScrim, spawn_modal, spawn_modal_actions, spawn_modal_button,
@@ -256,6 +256,7 @@ enum SettingsButton {
     /// local-only mode.
     ToggleAnalytics,
     /// Scan `user_theme_dir()` for new `.zip` files and import each one.
+    #[cfg(not(target_arch = "wasm32"))]
     ScanThemes,
     SyncNow,
     /// Open the sync-server Connect modal (shown when backend = Local).
@@ -318,6 +319,7 @@ impl SettingsButton {
             SettingsButton::SelectCardBack(_) => 70,
             SettingsButton::SelectBackground(_) => 80,
             SettingsButton::SelectTheme(_) => 85,
+            #[cfg(not(target_arch = "wasm32"))]
             SettingsButton::ScanThemes => 86,
             // Sync section
             SettingsButton::SyncNow => 90,
@@ -1256,6 +1258,7 @@ fn handle_settings_buttons(
                     changed.write(SettingsChangedEvent(settings.0.clone()));
                 }
             }
+            #[cfg(not(target_arch = "wasm32"))]
             SettingsButton::ScanThemes => {
                 // Handled by `handle_scan_themes`.
             }
@@ -2723,6 +2726,7 @@ fn handle_scan_themes(
     }
 }
 
+#[cfg(not(target_arch = "wasm32"))]
 /// A small pill-shaped settings button, matching the style used in `sync_row`.
 fn pill_button(
     parent: &mut ChildSpawnerCommands,