Build index Maps for repeated `.find()` lookups in chat and document hooks

[MODSetter]

Description

Several hot paths use .find() inside .map(), creating O(n*m) lookups that scale with chat length and team/document count.

Vercel React Best Practices Rule: js-index-maps (7.2)

Files to change

1. surfsense_web/app/dashboard/[search_space_id]/new-chat/[[...chat_id]]/page.tsx (lines ~229-235)

return syncedMessages.map((msg) => {
  const member = msg.author_id ? membersData?.find((m) => m.user_id === msg.author_id) : null;
  const existingMsg = prev.find((m) => m.id === `msg-${msg.id}`);

Fix: Build Maps once before the loop:

const memberById = new Map(membersData?.map(m => [m.user_id, m]) ?? []);
const prevById = new Map(prev.map(m => [m.id, m]));

return syncedMessages.map((msg) => {
  const member = msg.author_id ? memberById.get(msg.author_id) : null;
  const existingMsg = prevById.get(`msg-${msg.id}`);

2. surfsense_web/hooks/use-documents.ts (lines ~249-251)

const liveItem = validItems.find((v) => v.id === existing.id);

Fix:

const liveById = new Map(validItems.map(v => [v.id, v]));
// Then: liveById.get(existing.id)

3. surfsense_web/hooks/use-inbox.ts (lines ~160-161)

const liveItem = recentItems.find((v) => v.id === existing.id);

Fix: Same Map pattern.

Acceptance criteria

• No .find() inside .map() loops for the listed patterns
• All lookups use pre-built Map with .get()
• Chat messages, documents, and inbox items still display correctly

[JoeMakuta]

I can work on this @MODSetter