feat(vegas): let live content keep its place in the ticker (#457)

* 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

* 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

* fix(vegas): stop the heaviest plugin doubling across the cycle seam

Smooth Weighted Round-Robin spaces repeats well within a pass, but it
schedules the heaviest item first and usually last as well. The strip
loops, so those two are neighbours: the marquee showed the same plugin
twice running at exactly the one join a within-cycle check cannot see.
Observed on a live rig at 28 slots -- gaps of 6, 7, 7, 7 and then 1.

Rotating the list does not fix it. Rotation preserves the cyclic order
exactly, so it moves where the seam is drawn rather than the adjacency
itself; the trailing entry has to be swapped with one from the middle.

The first version swapped with the first slot that merely fitted, which
undid the spacing this exists to protect -- it moved a repeat from a gap
of 7 into a gap of 2, more clumped than the seam had ever been. It now
picks the candidate furthest from any other appearance, so the repeat
lands in the widest gap.

Left alone when no candidate exists. A plugin holding most of the slots
has to neighbour itself, and scheduling it is better than refusing to.

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

* fix(vegas): stop the seam repair creating the duplicate it removes

Swapping the trailing repeat with a middle slot moves two elements, and
the candidate filter only guarded one of them. It checked the neighbours
`repeated` would acquire at j, but not what the displaced element would
sit beside at the end -- so ['a','b','c','d','x','y','x','a'] came back
as [...,'x','x'], the seam duplicate traded for a fresh one. Reported by
CodeRabbit with that exact case.

Adding the missing condition fixed it and immediately broke something
else: schedule[j] is schedule[-2] when j is the second-to-last slot, so
that candidate was always excluded, and ['a','b','c','a'] lost the only
repair it has. The same class of mistake twice, from reasoning about
which neighbours two moved elements end up with.

So it no longer reasons. It performs each candidate swap, counts the
cyclic duplicates in the result, and keeps the best one that has none --
preferring whichever leaves the boosted plugin most evenly spread. When
no such swap exists the schedule is returned untouched, which is the
unavoidable case: a plugin holding most of the slots has to neighbour
itself.

Fuzzed across 6,956 seam schedules: none made worse, none lost an entry.

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

---------

Co-authored-by: Claude Opus 5 (1M context) <noreply@anthropic.com>

src/vegas_mode/stream_manager.py

@@ -406,6 +406,8 @@ class StreamManager:
         )
         logger.info("Ordered plugins: %s", ordered_plugins)
 
+        ordered_plugins = self._apply_priority_weights(ordered_plugins)
+
         # Atomically update shared state under lock to avoid races with prefetchers
         with self._buffer_lock:
             self._ordered_plugins = ordered_plugins
@@ -417,6 +419,143 @@ class StreamManager:
 
         logger.info("=" * 60)
 
+    def _plugin_weight(self, plugin_id: str) -> int:
+        """Slots per cycle for one plugin.
+
+        A plugin may answer for itself via get_vegas_priority_weight() -- the
+        only way favorite-team awareness can reach here, since the core can see
+        that a game is live but not whose. When it declines (returns None, the
+        default), live content earns ``live_weight`` and everything else 1.
+        """
+        plugin = None
+        try:
+            plugin = self.plugin_manager.plugins.get(plugin_id)
+        except (AttributeError, TypeError):
+            return 1
+        if plugin is None:
+            return 1
+
+        try:
+            if hasattr(plugin, 'get_vegas_priority_weight'):
+                declared = plugin.get_vegas_priority_weight()
+                if declared is not None:
+                    return max(1, min(10, int(declared)))
+        except Exception:
+            # Deliberately falls through to the core's own live check rather
+            # than demoting to 1. The plugin's weight calculation is broken,
+            # but has_live_priority() and has_live_content() are separate
+            # methods guarded separately below -- a plugin that genuinely has
+            # a live game should still get live_weight for it.
+            logger.exception("[%s] get_vegas_priority_weight() failed", plugin_id)
+
+        try:
+            if (hasattr(plugin, 'has_live_priority')
+                    and hasattr(plugin, 'has_live_content')
+                    and plugin.has_live_priority()
+                    and plugin.has_live_content()):
+                return self.config.live_weight
+        except Exception:
+            logger.exception("[%s] live-content check failed", plugin_id)
+        return 1
+
+    def _apply_priority_weights(self, ordered: List[str]) -> List[str]:
+        """Expand the rotation so weighted plugins take several turns per cycle.
+
+        Smooth Weighted Round-Robin, the same scheduler the sports plugins use
+        to rotate their own games: a plugin of weight N appears N times per
+        cycle, and the repeats are spaced through the cycle rather than
+        clumped, so a live score is never three-in-a-row followed by a long
+        silence.
+
+        Returns the input unchanged when nothing is weighted, which is both the
+        common case and the pre-existing behaviour.
+        """
+        if not ordered or not self.config.live_in_ticker:
+            return ordered
+
+        weights = {pid: self._plugin_weight(pid) for pid in ordered}
+        total = sum(weights.values())
+        if total <= len(ordered):
+            return ordered          # nothing boosted; plain round robin
+
+        current = {pid: 0 for pid in ordered}
+        schedule: List[str] = []
+        for _ in range(total):
+            for pid in ordered:
+                current[pid] += weights[pid]
+            picked = max(current, key=lambda p: current[p])
+            current[picked] -= total
+            schedule.append(picked)
+
+        schedule = self._unclump_seam(schedule)
+
+        boosted = {p: w for p, w in weights.items() if w > 1}
+        logger.info(
+            "Vegas rotation weighted: %d slots for %d plugins (boosted: %s)",
+            len(schedule), len(ordered), boosted)
+        return schedule
+
+    @staticmethod
+    def _unclump_seam(schedule: List[str]) -> List[str]:
+        """Stop the heaviest plugin sitting on both ends of the cycle.
+
+        Smooth Weighted Round-Robin spaces repeats well *within* a pass, but
+        it schedules the heaviest item first and often last too. The strip
+        loops, so those two are neighbours: the one place the marquee shows
+        the same plugin twice running is the seam between cycles.
+
+        Rotating the list cannot fix this. Rotation preserves the cyclic order
+        exactly, so it only moves where the seam is drawn, not the adjacency
+        itself. The trailing entry has to be swapped with one from the middle
+        whose neighbours differ from it, which breaks the pair without
+        creating another.
+
+        Left alone when no such position exists -- a rotation short enough or
+        lopsided enough to have none is one where the plugin is unavoidably
+        adjacent to itself anyway.
+        """
+        if len(schedule) < 3 or schedule[0] != schedule[-1]:
+            return schedule
+
+        repeated = schedule[-1]
+        size = len(schedule)
+
+        def cyclic_doubles(seq) -> int:
+            return sum(1 for i in range(size) if seq[i] == seq[(i + 1) % size])
+
+        def clearance(seq, value) -> int:
+            """Smallest cyclic gap between appearances of `value`."""
+            at = [i for i, v in enumerate(seq) if v == value]
+            if len(at) < 2:
+                return size
+            return min(min((b - a) % size, (a - b) % size)
+                       for i, a in enumerate(at) for b in at[i + 1:])
+
+        # Try each swap and judge the result, rather than reasoning about which
+        # neighbours the two moved elements will end up with. That reasoning is
+        # where the first version went wrong: it guarded the slot `repeated`
+        # moves into but not the one the displaced element lands in, so
+        # ['a','b','c','d','x','y','x','a'] came back ending ['x','x'] -- the
+        # seam duplicate traded for a fresh one.
+        best = None
+        best_clearance = -1
+        for j in range(1, size - 1):
+            candidate = list(schedule)
+            candidate[j], candidate[-1] = candidate[-1], candidate[j]
+            if cyclic_doubles(candidate):
+                continue
+            # Among the repairs that work, prefer the one that leaves the
+            # boosted plugin most evenly spread; taking the first that merely
+            # fits moved a repeat from a gap of 7 into a gap of 2.
+            spread = clearance(candidate, repeated)
+            if spread > best_clearance:
+                best, best_clearance = candidate, spread
+
+        # None exists when the value is unavoidably adjacent to itself -- a
+        # plugin holding most of the slots has to be. Schedule it as it is
+        # rather than refuse.
+        return best if best is not None else schedule
+
     def _prefetch_content(self, count: int = 1) -> None:
         """
         Prefetch content for upcoming plugins.