feat: Y2K dither theme, filter toolbars, chat bubble widget; fix alignment root causes

- theme rework (user request): white paper bg, brown ink, ordered-dither
  halftone textures, hard offset Y2K shadows, dithered masthead bands;
  dark theme matched; token test + DECISIONS updated
- fix: .card + .card stacking margin leaked into grid layouts, shifting
  every card except the first (the 'always the first item' reports)
- fix: CSP style-src 'self' silently dropped every inline style attribute
  (misaligned save button, stat values, editor attach button, bell badge);
  styles now allow inline, scripts remain strict per §12
- fix: [hidden] is now display:none !important so flex containers cannot
  defeat it (chat panel/footers)
- board + metrics filters live in boxed .toolbar rows with baseline-aligned
  controls; metric stat cards use a uniform .stat layout
- new-conversation dialog: fixed 440px width and 180px results list (no
  more resizing while searching), full-width result rows, picked people
  drop out of the list
- floating messages bubble bottom-right on all pages (except /messages):
  unread badge, mini panel with conversation list, thread view, quick
  composer, live WS updates; toasts moved up to clear it

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

web/templates/metrics.html

@@ -1,15 +1,20 @@
 {{define "content"}}
-<div class="spread">
-  <h1>Metrics</h1>
-  <span>
-    <label class="muted" style="display:inline">From <input type="date" id="m-from" style="width:auto"></label>
-    <label class="muted" style="display:inline">To <input type="date" id="m-to" style="width:auto"></label>
-    <button class="btn small" id="m-apply">Apply</button>
-    <a class="btn small" id="m-csv" href="#">Export CSV</a>
-  </span>
-</div>
+<h1>Metrics</h1>
 <div class="error-box" id="error" role="alert"></div>
 
+<div class="toolbar mt">
+  <div class="field tight">
+    <label for="m-from">From</label>
+    <input type="date" id="m-from">
+  </div>
+  <div class="field tight">
+    <label for="m-to">To</label>
+    <input type="date" id="m-to">
+  </div>
+  <button class="btn" id="m-apply">Apply</button>
+  <a class="btn" id="m-csv" href="#">Export CSV</a>
+</div>
+
 <section id="dev-metrics" hidden>
   <div class="grid mt" id="dev-cards"></div>
   <div class="card mt"><h2>Earnings over time (weekly)</h2><div id="dev-weekly"></div></div>
@@ -17,12 +22,11 @@
 </section>
 
 <section id="cons-metrics" hidden>
-  <div class="spread mt">
-    <span>
-      <label class="muted" style="display:inline">Customer
-        <select id="m-customer" style="width:auto"><option value="">All</option></select>
-      </label>
-    </span>
+  <div class="toolbar mt">
+    <div class="field tight">
+      <label for="m-customer">Customer</label>
+      <select id="m-customer"><option value="">All</option></select>
+    </div>
   </div>
   <div class="grid mt" id="cons-cards"></div>
   <div class="card mt"><h2>Awarded over time (weekly)</h2><div id="cons-weekly"></div></div>