mavweb: unify UI — shared ui.css + nav partial across all pages

One theme (the PWA's dark palette) for dash/history/trace/notifications/
tools/passkey via static/ui.css; shared nav template with active-page
highlight; tables wrapped in .scroll so they pan on phones; PWA nav no
longer clips the RU/EN toggle; dash 'updated' timestamp fixed (selector
matched nothing). AGENTS.md documents the local preview/screenshot recipe.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01ASstMtsZWLSRcD1Tq8T68Q

cmd/mavweb/static/ui.css

@@ -0,0 +1,64 @@
+/* maven web ui — one theme for every server-rendered page.
+   Palette and type mirror the PWA (static/index.html): dark, restrained,
+   #00aaff accent. Pages carry NO inline <style> beyond true one-offs. */
+:root{
+  --bg:#111; --panel:#1a1a2e; --line:#222; --border:#333;
+  --fg:#ddd; --soft:#aaa; --muted:#888; --dim:#555;
+  --accent:#00aaff; --ok:#00ff88; --warn:#ffaa00; --err:#ff4444;
+}
+*{box-sizing:border-box}
+body{background:var(--bg);color:var(--fg);font:14px/1.5 system-ui,sans-serif;
+  margin:0;padding:1rem;-webkit-text-size-adjust:100%}
+h1,h2{font-weight:400;color:var(--muted);letter-spacing:.1em;text-transform:uppercase}
+h1{font-size:1.2rem;margin:.2rem 0 .6rem}
+h2{font-size:.95rem;margin:1.4rem 0 .3rem}
+h1 small,h2 small{color:var(--dim);letter-spacing:0;text-transform:none}
+a{color:var(--accent);text-decoration:none}
+a:hover{text-decoration:underline}
+
+/* shared site nav (the "nav" template partial) */
+nav.site{display:flex;gap:1rem;flex-wrap:wrap;align-items:center;
+  border-bottom:1px solid var(--line);padding-bottom:.6rem;margin-bottom:1rem}
+nav.site a{font-size:.8rem;letter-spacing:.08em;text-transform:uppercase;color:var(--dim)}
+nav.site a:hover{color:var(--fg);text-decoration:none}
+nav.site a.active{color:var(--accent)}
+
+/* tables: always inside a .scroll wrapper so wide data pans instead of
+   breaking the page on a phone */
+.scroll{overflow-x:auto}
+table{width:100%;border-collapse:collapse;margin-top:.4rem}
+th,td{padding:.35rem .5rem;text-align:left;vertical-align:top;
+  border-bottom:1px solid var(--line)}
+th{color:var(--dim);font-size:.75rem;text-transform:uppercase;
+  letter-spacing:.05em;white-space:nowrap}
+td{color:var(--soft)}
+.mono{font-family:ui-monospace,SFMono-Regular,Menlo,monospace}
+code,.key{font-family:ui-monospace,SFMono-Regular,Menlo,monospace;color:var(--ok)}
+
+/* status colors — nudge outcomes, presence, booleans */
+.pending{color:var(--muted)}.acted{color:var(--ok)}
+.snoozed{color:var(--warn)}.ignored{color:var(--err)}
+.pres,.green{color:var(--ok)}.away,.gray{color:var(--muted)}.red{color:var(--err)}
+.badge{font-size:.75rem;color:var(--dim);background:var(--panel);
+  padding:.15rem .35rem;border-radius:3px;white-space:nowrap}
+.updated,.muted{color:var(--dim);font-size:.85rem}
+.empty{color:var(--dim);padding:2rem;text-align:center}
+.voided{opacity:.45;text-decoration:line-through}
+.void-badge{color:var(--dim);font-size:.8rem;margin-right:.3rem}
+
+/* controls */
+button{font:inherit;font-size:.85rem;background:var(--panel);color:var(--fg);
+  border:1px solid var(--border);border-radius:3px;padding:.25rem .6rem;cursor:pointer}
+button:hover{border-color:var(--accent)}
+button:disabled{opacity:.4;cursor:not-allowed}
+input[type=text]{font:inherit;font-size:.85rem;background:var(--bg);color:var(--fg);
+  border:1px solid var(--border);border-radius:3px;padding:.25rem .4rem;max-width:100%}
+label{color:var(--soft)}
+
+/* inline feedback (/history revert, /tools enable, /auth/passkey) */
+.msg{margin:.6rem 0;padding:.5rem .7rem;border-radius:3px;border:1px solid var(--line)}
+.msg-ok{border-color:var(--ok);color:var(--ok)}
+.msg-err{border-color:var(--err);color:var(--err)}
+
+details{color:var(--soft);font-size:.85rem}
+summary{cursor:pointer;color:var(--dim)}