feat(vegas): let live content keep its place in the ticker

Live content used to preempt Vegas outright: while any plugin reported
live priority the display controller refused to run the ticker at all and
showed a full-screen scoreboard instead. Keeping the marquee meant not
seeing live scores; seeing live scores meant losing the marquee.

Two changes, both off by default.

vegas_scroll.live_in_ticker keeps the ticker running through a live game.
Three places assumed the takeover and all three now honour it: the
controller's gate, the coordinator's per-frame pause, and the rotation
switch that would otherwise move current_mode_index underneath a ticker
that never yields.

And the rotation is no longer a strict round robin. It was one slot per
plugin per cycle, so with a dozen plugins enabled a live score came round
once a lap and could be minutes old on screen. A plugin can now hold
several slots, placed by Smooth Weighted Round-Robin -- the same
scheduler the sports plugins already use to rotate their own games. The
property that matters is that repeats are spread through the cycle
rather than clumped: three in a row and then silence would be worse than
no boost at all.

Weight comes from the plugin first, via a new optional
get_vegas_priority_weight(), then from the core: live content earns
live_weight, everything else 1. So existing plugins gain the behaviour
without changes, and the hook exists for the one thing the core cannot
work out -- the core can see that a game is live but not whose, so only
the plugin can say a favorite is playing.

Documented in ADVANCED_FEATURES (worked example, why weights are per
plugin not per game, and that frequency is not freshness),
CONFIG_REFERENCE, PLUGIN_API_REFERENCE, and the config template.

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

test/test_vegas_live_weighting.py

@@ -0,0 +1,171 @@
+"""Tests that live content can take extra turns inside the Vegas ticker.
+
+Vegas was a strict round robin -- every plugin exactly once per cycle -- and
+live content did not appear in it at all, because the display controller
+refused to run the ticker while anything was live. With a dozen plugins
+enabled that left a live score either absent or minutes stale.
+
+Two things change, both off by default. `live_in_ticker` keeps the marquee
+running instead of yielding to a full-screen takeover, and the rotation is
+expanded by Smooth Weighted Round-Robin so a weighted plugin gets several
+slots per cycle, spaced through it rather than clumped.
+
+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 it.
+"""
+
+from unittest.mock import Mock
+
+import pytest
+
+from src.vegas_mode.config import VegasModeConfig
+from src.vegas_mode.stream_manager import StreamManager
+
+
+class FakePlugin:
+    def __init__(self, live=False, declared=None, raises=False):
+        self._live = live
+        self._declared = declared
+        self._raises = raises
+        self.enabled = True
+
+    def has_live_priority(self):
+        if self._raises:
+            raise RuntimeError("plugin blew up")
+        return self._live
+
+    def has_live_content(self):
+        return self._live
+
+    def get_vegas_priority_weight(self):
+        if self._raises:
+            raise RuntimeError("plugin blew up")
+        return self._declared
+
+
+def _manager(plugins, **cfg):
+    config = VegasModeConfig(live_in_ticker=cfg.pop('live_in_ticker', True), **cfg)
+    pm = Mock()
+    pm.plugins = plugins
+    sm = StreamManager.__new__(StreamManager)
+    sm.config = config
+    sm.plugin_manager = pm
+    return sm
+
+
+def _counts(schedule):
+    return {p: schedule.count(p) for p in set(schedule)}
+
+
+def _max_gap(schedule, plugin_id):
+    """Largest gap between consecutive appearances, wrapping around."""
+    at = [i for i, p in enumerate(schedule) if p == plugin_id]
+    if len(at) < 2:
+        return len(schedule)
+    gaps = [b - a for a, b in zip(at, at[1:])]
+    gaps.append(len(schedule) - at[-1] + at[0])
+    return max(gaps)
+
+
+class TestWeightsComeFromTheRightPlace:
+    def test_a_quiet_plugin_gets_one_slot(self):
+        sm = _manager({'clock': FakePlugin()})
+        assert sm._plugin_weight('clock') == 1
+
+    def test_live_content_earns_the_configured_weight(self):
+        sm = _manager({'mlb': FakePlugin(live=True)}, live_weight=4)
+        assert sm._plugin_weight('mlb') == 4
+
+    def test_a_plugin_may_answer_for_itself(self):
+        # The only route for favorite-team awareness: the core can see that a
+        # game is live, not whose.
+        sm = _manager({'mlb': FakePlugin(live=True, declared=7)}, live_weight=3)
+        assert sm._plugin_weight('mlb') == 7
+
+    def test_declaring_none_defers_to_the_core(self):
+        sm = _manager({'mlb': FakePlugin(live=True, declared=None)}, live_weight=3)
+        assert sm._plugin_weight('mlb') == 3
+
+    def test_a_declared_weight_is_clamped(self):
+        sm = _manager({'a': FakePlugin(declared=99), 'b': FakePlugin(declared=0)})
+        assert sm._plugin_weight('a') == 10
+        assert sm._plugin_weight('b') == 1
+
+    def test_a_plugin_that_raises_does_not_break_the_rotation(self):
+        sm = _manager({'bad': FakePlugin(raises=True)})
+        assert sm._plugin_weight('bad') == 1
+
+    def test_an_unknown_plugin_weighs_one(self):
+        assert _manager({})._plugin_weight('ghost') == 1
+
+
+class TestTheSchedule:
+    def test_nothing_weighted_leaves_the_order_untouched(self):
+        order = ['weather', 'clock', 'news']
+        sm = _manager({p: FakePlugin() for p in order})
+        assert sm._apply_priority_weights(order) == order
+
+    def test_off_by_default_the_order_is_untouched(self):
+        order = ['weather', 'mlb', 'news']
+        sm = _manager({'weather': FakePlugin(), 'mlb': FakePlugin(live=True),
+                       'news': FakePlugin()}, live_in_ticker=False, live_weight=3)
+        assert sm._apply_priority_weights(order) == order
+
+    def test_a_live_plugin_takes_its_share_of_slots(self):
+        order = ['weather', 'mlb', 'news', 'clock']
+        sm = _manager({'weather': FakePlugin(), 'mlb': FakePlugin(live=True),
+                       'news': FakePlugin(), 'clock': FakePlugin()},
+                      live_weight=3)
+        schedule = sm._apply_priority_weights(order)
+        counts = _counts(schedule)
+        assert counts['mlb'] == 3, counts
+        assert counts['weather'] == counts['news'] == counts['clock'] == 1, counts
+        assert len(schedule) == 6
+
+    def test_every_plugin_still_appears(self):
+        # A boost must not starve anything out of the cycle.
+        order = ['a', 'b', 'c', 'd', 'e', 'f']
+        plugins = {p: FakePlugin() for p in order}
+        plugins['a'] = FakePlugin(live=True, declared=10)
+        sm = _manager(plugins)
+        schedule = sm._apply_priority_weights(order)
+        assert set(schedule) == set(order), set(order) - set(schedule)
+
+    def test_repeats_are_spread_not_clumped(self):
+        # The point of Smooth Weighted Round-Robin. Three-in-a-row followed by
+        # a long silence would be worse than not boosting at all.
+        order = ['weather', 'mlb', 'news', 'clock', 'stocks', 'f1']
+        plugins = {p: FakePlugin() for p in order}
+        plugins['mlb'] = FakePlugin(live=True)
+        sm = _manager(plugins, live_weight=3)
+        schedule = sm._apply_priority_weights(order)
+
+        assert _counts(schedule)['mlb'] == 3
+        # Evenly spread over 8 slots means a gap of about 3, never 6.
+        assert _max_gap(schedule, 'mlb') <= 4, schedule
+        # And never twice running.
+        assert not any(a == b == 'mlb' for a, b in zip(schedule, schedule[1:])), schedule
+
+    def test_a_favorite_outranks_another_live_game(self):
+        order = ['weather', 'mlb', 'nhl']
+        sm = _manager({'weather': FakePlugin(),
+                       'mlb': FakePlugin(live=True, declared=5),
+                       'nhl': FakePlugin(live=True)}, live_weight=2)
+        counts = _counts(sm._apply_priority_weights(order))
+        assert counts['mlb'] == 5 and counts['nhl'] == 2 and counts['weather'] == 1, counts
+
+    def test_an_empty_rotation_is_harmless(self):
+        assert _manager({})._apply_priority_weights([]) == []
+
+
+class TestConfigParsing:
+    def test_defaults_preserve_todays_behaviour(self):
+        cfg = VegasModeConfig.from_config({})
+        assert cfg.live_in_ticker is False
+        assert cfg.live_weight == 3 and cfg.favorite_live_weight == 5
+
+    @pytest.mark.parametrize("given,expected", [(0, 1), (-4, 1), (99, 10), (4, 4)])
+    def test_weights_are_clamped(self, given, expected):
+        cfg = VegasModeConfig.from_config(
+            {'display': {'vegas_scroll': {'live_weight': given}}})
+        assert cfg.live_weight == expected