feat(gif): recently-used GIFs in the picker

The GIF picker was a bare Giphy search grid with no memory of what you've
sent, so re-sending a go-to reaction GIF meant re-typing the search every
time. Add a "Recent" row at the top of the picker (default view; hidden
while searching) for one-click re-sending.

- New persisted state state/recentGifs.ts: recentGifsAtom (localStorage,
  cinny_recent_gifs_v1, getOnInit) + pure addRecentGif (dedupe-by-url
  move-to-front, cap 16, ignore empty url), with 5 unit tests.
- GifPicker records every sent GIF (from search or the Recent row) to the
  front, and renders a 3-up thumbnail grid of recents above the search
  grid when there are recents and no active search term. Section label
  matches the picker's existing `// GIF_SEARCH` treatment (lotusTerminal)
  or a muted label otherwise.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/app/components/GifPicker.tsx

@@ -1,10 +1,12 @@
 import React, { useCallback } from 'react';
 import FocusTrap from 'focus-trap-react';
+import { useAtom } from 'jotai';
 import { Grid, SearchBar, SearchContext, SearchContextManager } from '@giphy/react-components';
 import { IGif } from '@giphy/js-types';
 import { Box, color, config } from 'folds';
 import { useSetting } from '../state/hooks/settings';
 import { settingsAtom } from '../state/settings';
+import { addRecentGif, RecentGif, recentGifsAtom } from '../state/recentGifs';
 
 const PICKER_WIDTH = 312;
 const PICKER_WIDTH_CSS = `min(${PICKER_WIDTH}px, calc(100vw - 16px))`;
@@ -15,22 +17,108 @@ type GifPickerInnerProps = {
   lotusTerminal: boolean;
 };
 
+// Small monospace section header matching the picker's `// GIF_SEARCH` treatment
+// (lotusTerminal) / a muted label otherwise.
+function SectionLabel({ text, lotusTerminal }: { text: string; lotusTerminal: boolean }) {
+  if (lotusTerminal) {
+    return (
+      <div
+        style={{
+          padding: '4px 2px',
+          fontFamily: "'JetBrains Mono', 'Cascadia Code', monospace",
+          fontSize: '10px',
+          fontWeight: 700,
+          letterSpacing: '0.1em',
+          color: 'var(--lt-accent-orange)',
+          userSelect: 'none',
+        }}
+      >
+        {`// ${text.toUpperCase()}`}
+      </div>
+    );
+  }
+  return (
+    <div
+      style={{
+        padding: '2px 2px 4px',
+        fontSize: '11px',
+        fontWeight: 600,
+        color: color.Surface.OnContainer,
+        opacity: 0.6,
+        userSelect: 'none',
+      }}
+    >
+      {text}
+    </div>
+  );
+}
+
+function RecentGifs({
+  recents,
+  lotusTerminal,
+  onPick,
+}: {
+  recents: RecentGif[];
+  lotusTerminal: boolean;
+  onPick: (url: string, width: number, height: number) => void;
+}) {
+  return (
+    <div style={{ marginBottom: 8 }}>
+      <SectionLabel text="Recent" lotusTerminal={lotusTerminal} />
+      <div style={{ display: 'grid', gridTemplateColumns: 'repeat(3, 1fr)', gap: 4 }}>
+        {recents.map((g) => (
+          <button
+            key={g.url}
+            type="button"
+            aria-label="Send recent GIF"
+            onClick={() => onPick(g.url, g.width, g.height)}
+            style={{
+              padding: 0,
+              border: 'none',
+              background: 'transparent',
+              cursor: 'pointer',
+              height: 72,
+              borderRadius: lotusTerminal ? '4px' : '8px',
+              overflow: 'hidden',
+            }}
+          >
+            <img
+              src={g.url}
+              alt=""
+              loading="lazy"
+              style={{ width: '100%', height: '100%', objectFit: 'cover', display: 'block' }}
+            />
+          </button>
+        ))}
+      </div>
+    </div>
+  );
+}
+
 function GifPickerInner({ onSelect, requestClose, lotusTerminal }: GifPickerInnerProps) {
-  const { fetchGifs, searchKey } = React.useContext(SearchContext);
+  const { fetchGifs, searchKey, term } = React.useContext(SearchContext);
+  const [recents, setRecents] = useAtom(recentGifsAtom);
+
+  const sendGif = useCallback(
+    (url: string, width: number, height: number) => {
+      setRecents((prev) => addRecentGif(prev, { url, width, height }));
+      onSelect(url, width, height);
+      requestClose();
+    },
+    [onSelect, requestClose, setRecents],
+  );
 
   const handleClick = useCallback(
     (gif: IGif, e: React.SyntheticEvent) => {
       e.preventDefault();
       const r = gif.images.downsized ?? gif.images.original;
-      const { url } = r;
-      const width = Number(r.width) || 200;
-      const height = Number(r.height) || 200;
-      onSelect(url, width, height);
-      requestClose();
+      sendGif(r.url, Number(r.width) || 200, Number(r.height) || 200);
     },
-    [onSelect, requestClose],
+    [sendGif],
   );
 
+  const showRecents = recents.length > 0 && !(term ?? '').trim();
+
   return (
     <Box direction="Column" style={{ width: PICKER_WIDTH_CSS }}>
       {lotusTerminal && (
@@ -57,6 +145,9 @@ function GifPickerInner({ onSelect, requestClose, lotusTerminal }: GifPickerInne
       <div
         style={{ overflowY: 'auto', overflowX: 'hidden', maxHeight: '340px', padding: '0 8px 8px' }}
       >
+        {showRecents && (
+          <RecentGifs recents={recents} lotusTerminal={lotusTerminal} onPick={sendGif} />
+        )}
         <Grid
           key={searchKey}
           fetchGifs={fetchGifs}