fix(vegas): carry the new keys through config, and correct two docs

Three findings from CodeRabbit, all valid.

to_dict() and update() enumerate keys explicitly and had not learned the
three new ones, so get_status() never reported them and a live config
change never applied -- turning live_in_ticker on in the web UI would
have done nothing until a restart. update() clamps the weights exactly
as from_config does.

The vegas_scroll key count in ADVANCED_FEATURES said 29; the template
has 30. My arithmetic, not the reviewer's.

The third was a documentation error rather than a code one, and I have
fixed it the other way round. The docs claimed a raising
get_vegas_priority_weight() is treated as weight 1. The code instead
falls through to the core's own live-content check, and that is the
better behaviour: the hook is only how a plugin asks for *more* than
live_weight, and has_live_priority/has_live_content are separate methods
guarded separately, so a plugin with a broken weight calculation should
lose the favorite distinction and keep the live boost. Said so in the
code, the base-plugin docstring and the API reference.

The test fake now fails in each place independently, because the two
failures mean different things: a broken hook still earns live_weight, a
plugin that cannot say whether it is live has nothing to fall back on
and weighs 1.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ui/code/session_01Udr6MfaFLUPhX5Fgo67Jf5

src/vegas_mode/config.py

@@ -236,6 +236,9 @@ class VegasModeConfig:
             'lead_in_width': self.lead_in_width,
             'plugins_per_cycle': self.plugins_per_cycle,
             'max_plugin_width_ratio': self.max_plugin_width_ratio,
+            'live_in_ticker': self.live_in_ticker,
+            'live_weight': self.live_weight,
+            'favorite_live_weight': self.favorite_live_weight,
             'overflow_mode': self.overflow_mode,
             'plugin_order': self.plugin_order,
             'excluded_plugins': list(self.excluded_plugins),
@@ -403,6 +406,15 @@ class VegasModeConfig:
 
         if 'enabled' in vegas_config:
             self.enabled = vegas_config['enabled']
+        if 'live_in_ticker' in vegas_config:
+            self.live_in_ticker = bool(vegas_config['live_in_ticker'])
+        # Clamped exactly as from_config does: a weight below 1 would drop the
+        # plugin from the rotation, and a huge one starves everything else.
+        if 'live_weight' in vegas_config:
+            self.live_weight = max(1, min(10, int(vegas_config['live_weight'])))
+        if 'favorite_live_weight' in vegas_config:
+            self.favorite_live_weight = max(
+                1, min(10, int(vegas_config['favorite_live_weight'])))
         if 'scroll_speed' in vegas_config:
             self.scroll_speed = float(vegas_config['scroll_speed'])
         if 'separator_width' in vegas_config: