feat(vegas): keep live games in the ticker by default

display.vegas_scroll.live_in_ticker now defaults to true: through a live
game the marquee keeps running and the live scoreboard takes extra turns in
it -- its cards updating in place while they scroll -- instead of the ticker
giving way to the full-screen scoreboard.

The new default would reach nobody on its own: every existing config holds
an explicit false copied from the template (there was no control for it),
and the template merge only adds missing keys. ConfigManager therefore turns
a stored false on once, with a backup, and records live_in_ticker_migrated
so a false chosen afterwards stays. The marker is never in the template.

A "Keep live games in the ticker" checkbox under Vegas mode sets it. Tests
that pin the full-screen takeover now say live_in_ticker=false.

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

src/config_manager.py

@@ -451,8 +451,10 @@ class ConfigManager:
                 template_config = json.load(f)
             
             # Check if migration is needed
-            if self._config_needs_migration(self.config, template_config):
-                self.logger.info("Config migration needed - adding new configuration items with defaults")
+            needs_merge = self._config_needs_migration(self.config, template_config)
+            if needs_merge or self._live_in_ticker_needs_migration():
+                if needs_merge:
+                    self.logger.info("Config migration needed - adding new configuration items with defaults")
                 
                 # Create backup of current config
                 backup_path = f"{self.config_path}.backup"
@@ -461,7 +463,9 @@ class ConfigManager:
                 self.logger.info(f"Created backup of current config at {os.path.abspath(backup_path)}")
                 
                 # Merge template defaults into current config
-                self._merge_template_defaults(self.config, template_config)
+                if needs_merge:
+                    self._merge_template_defaults(self.config, template_config)
+                self._migrate_live_in_ticker_default()
                 
                 # save_config_atomic strips the merged secrets back out and
                 # keeps the file's owner and mode.
@@ -482,6 +486,44 @@ class ConfigManager:
             self.logger.error(f"Error during config migration: {e}")
             # Don't raise - continue with current config
 
+    #: Set in display.vegas_scroll once _migrate_live_in_ticker_default() has
+    #: run. Never in the template: the template merge would add it first, and
+    #: the flip would then never run.
+    LIVE_IN_TICKER_MARKER = 'live_in_ticker_migrated'
+
+    def _vegas_scroll_section(self) -> Optional[Dict[str, Any]]:
+        display = self.config.get('display')
+        vegas = display.get('vegas_scroll') if isinstance(display, dict) else None
+        return vegas if isinstance(vegas, dict) else None
+
+    def _live_in_ticker_needs_migration(self) -> bool:
+        vegas = self._vegas_scroll_section()
+        return vegas is not None and not vegas.get(self.LIVE_IN_TICKER_MARKER)
+
+    def _migrate_live_in_ticker_default(self) -> None:
+        """Turn on live_in_ticker for a config that only ever had the old default. Once.
+
+        LEDMatrix 3.8.0 makes ``display.vegas_scroll.live_in_ticker`` true:
+        live games stay in the Vegas ticker, their cards updating while they
+        scroll, instead of the ticker giving way to the full-screen
+        scoreboard. Every existing config holds an explicit ``false`` copied
+        from the template -- there was no control for it -- and the template
+        merge only adds missing keys, so the new default would reach nobody.
+        This rewrites that ``false`` once and marks the config, so a
+        ``false`` chosen afterwards (the Vegas checkbox, or by hand) stays.
+        """
+        vegas = self._vegas_scroll_section()
+        if vegas is None or vegas.get(self.LIVE_IN_TICKER_MARKER):
+            return
+        vegas[self.LIVE_IN_TICKER_MARKER] = True
+        if vegas.get('live_in_ticker') is False:
+            vegas['live_in_ticker'] = True
+            self.logger.info(
+                "Vegas mode now keeps live games in the ticker (the new default): "
+                "display.vegas_scroll.live_in_ticker turned on, once. Untick "
+                "\"Keep live games in the ticker\" under Vegas mode for the "
+                "full-screen scoreboard.")
+
     def _config_needs_migration(self, current_config: Dict[str, Any], template_config: Dict[str, Any]) -> bool:
         """Check if config needs migration by comparing with template."""
         return self._has_new_keys(current_config, template_config)

src/display_controller.py

@@ -2206,7 +2206,7 @@ class DisplayController:
         """Whether live content should stay in the ticker instead of preempting it."""
         coordinator = self.vegas_coordinator
         config = getattr(coordinator, 'vegas_config', None)
-        return bool(getattr(config, 'live_in_ticker', False))
+        return bool(getattr(config, 'live_in_ticker', True))
 
     def _check_live_priority(self, advance=False):
         """Return the live-priority mode to display, or None if nothing is live.

src/vegas_mode/config.py

@@ -180,10 +180,13 @@ class VegasModeConfig:
 
     # --- Live content in the ticker -------------------------------------
     #
-    # By default a live game preempts Vegas entirely: the display controller
-    # refuses to run the ticker while any plugin reports live priority, and you
-    # get the full-screen scoreboard instead. Set live_in_ticker to keep the
-    # marquee running and let live content take extra turns within it.
+    # By default live content stays in the marquee and takes extra turns
+    # within it, its cards updating while they scroll (live elements, below).
+    # With live_in_ticker false a live game preempts Vegas entirely: the
+    # display controller refuses to run the ticker while any plugin reports
+    # live priority, and you get the full-screen scoreboard instead. (False
+    # was the default until 3.8.0; ConfigManager turns it on once for configs
+    # that still hold the old default.)
     #
     # The rotation is otherwise a strict round robin -- every plugin appears
     # exactly once per cycle -- so with a dozen plugins enabled a live score
@@ -193,7 +196,7 @@ class VegasModeConfig:
     # Weights are per plugin, not per game: a scoreboard showing four live
     # games still occupies one slot at a time, and rotates its own games within
     # that slot using its own favorite_live_boost.
-    live_in_ticker: bool = False
+    live_in_ticker: bool = True
 
     # Slots per cycle for a plugin reporting live content. 1 disables the boost
     # and restores the plain round robin.