adventure: give the Siege a war room instead of a Matrix-only rumour

The Siege is the one mechanic where the whole town works on a single
object, and it existed exclusively in Matrix — so anybody not in the room
at the time never knew it happened. A communal event nobody can see is a
communal event that fails.

gogobee now pushes the war room on the roster tick and Pete replaces its
copy, the same snapshot contract the board has and for the same reason:
the shared pool is state, not history, and a retried snapshot would be a
lie about how much HP is left.

/adventure/siege draws it. The load-bearing detail is one CSS line — the
health bar has a width transition, so a poll that lands a lower pool
slides the bar down instead of snapping it. That is the difference
between watching the town chip a boss down and reading a report about it.
Alongside: a countdown to the window's close, past sieges with the bar
each one ended on, and the muster split into who took today's bout and
who still has one going spare — the mechanic is one fight per person per
day, so that second column is a hit the town hasn't taken yet.

The opt-out rule here deliberately differs from the board's. The board
omits an opted-out player outright, because class + level + zone
re-identifies them. A Siege contributor is anonymised instead: their
damage is part of what the town did to the boss, and deleting it would
understate the shared effort and stop the totals adding up. They keep
their rank, lose their name, and carry no token — so there is no link
back to a page that names them. An opted-out player who never fought is
still omitted; there is nothing to account for.

siege_start / siege_win / siege_loss are wired on the gogobee side; the
templates for all three have been sitting unused in renderAdventure
since the section shipped.

internal/web/static/css/input.css

@@ -2757,3 +2757,78 @@ html[data-room] .pete-felt {
   .cmp-delta-up   { color: color-mix(in srgb, #3fa66a 65%, var(--ink)); background: color-mix(in srgb, #3fa66a 13%, var(--card)); }
   .cmp-delta-down { color: color-mix(in srgb, #c0392b 60%, var(--ink)); background: color-mix(in srgb, #c0392b 12%, var(--card)); }
 }
+
+@layer components {
+  /* The Siege war room. One rule carries the whole page: the health bar has a
+     width transition, so a poll that lands a lower pool *slides* the bar down
+     instead of snapping it. That is the difference between watching the town
+     chip a boss and reading a report about it, and it costs one line.
+     prefers-reduced-motion turns the slide off — the number is still correct,
+     it just arrives instantly.
+
+     The ember palette is deliberate and not the adventure purple: a siege is
+     the one thing on the site that should look like an emergency. It mixes a
+     fixed hue into --card/--ink like the map and compare chips do, so it lands
+     readable in all four phases without a dark: variant. */
+  .siege-track {
+    position: relative;
+    height: 1.75rem;
+    border-radius: 9999px;
+    overflow: hidden;
+    background: color-mix(in srgb, var(--ink) 12%, var(--card));
+    box-shadow: inset 0 2px 4px rgba(0,0,0,0.12);
+  }
+  .siege-fill {
+    height: 100%;
+    border-radius: 9999px;
+    background: linear-gradient(90deg, #e0562f 0%, #c0392b 60%, #8f1f16 100%);
+    transition: width 1.4s cubic-bezier(0.22, 0.61, 0.36, 1);
+  }
+  .siege-fill-spent { background: linear-gradient(90deg, #6b7280 0%, #4b5563 100%); }
+
+  /* A living siege breathes. Slow and low-contrast on purpose — it should read
+     as "this is happening now", not as a thing demanding to be clicked. */
+  .siege-live .siege-fill { animation: siege-pulse 3.2s ease-in-out infinite; }
+  @keyframes siege-pulse {
+    0%, 100% { filter: brightness(1); }
+    50%      { filter: brightness(1.12); }
+  }
+
+  .siege-chip {
+    display: inline-flex; align-items: center; gap: 0.3rem;
+    font-size: 11px; font-weight: 600; line-height: 1;
+    border-radius: 9999px; padding: 0.22rem 0.6rem;
+    border: 1px solid transparent;
+  }
+  .siege-chip-fought {
+    color: color-mix(in srgb, #3fa66a 65%, var(--ink));
+    background: color-mix(in srgb, #3fa66a 15%, var(--card));
+    border-color: color-mix(in srgb, #3fa66a 36%, transparent);
+  }
+  .siege-chip-waiting {
+    color: var(--warn);
+    background: color-mix(in srgb, var(--warn) 14%, var(--card));
+    border-color: color-mix(in srgb, var(--warn) 34%, transparent);
+  }
+  .siege-chip-held {
+    color: color-mix(in srgb, #3fa66a 65%, var(--ink));
+    background: color-mix(in srgb, #3fa66a 15%, var(--card));
+    border-color: color-mix(in srgb, #3fa66a 36%, transparent);
+  }
+  .siege-chip-fell {
+    color: color-mix(in srgb, #c0392b 60%, var(--ink));
+    background: color-mix(in srgb, #c0392b 15%, var(--card));
+    border-color: color-mix(in srgb, #c0392b 36%, transparent);
+  }
+
+  /* The past-siege bar: same track, smaller, and frozen at the pool the Siege
+     ended on. A won Siege ends at zero and draws as an empty track, which is
+     exactly the right picture. */
+  .siege-track-sm { height: 0.5rem; }
+  .siege-track-sm .siege-fill { transition: none; }
+
+  @media (prefers-reduced-motion: reduce) {
+    .siege-fill { transition: none; }
+    .siege-live .siege-fill { animation: none; }
+  }
+}