fix: move useEffect hooks before early return in ChatProfiles

[EyalAmitay]

Summary

• Fix React Rules of Hooks violation in ChatProfiles.tsx where two useEffect hooks were placed after an early return
• When config loads asynchronously (undefined → populated), the hook count changes between renders (8 → 10), causing React to throw "Rendered more hooks than during the previous render"
• Move the early return below both useEffect calls and add optional chaining guards so they no-op when config.chatProfiles is missing

Test plan

• pnpm type-check passes
• pnpm lint passes
• pnpm test (frontend unit tests) — 32/32 pass
• Manual: verify chat profiles load correctly when config has 2+ profiles
• Manual: verify component returns null gracefully when 0-1 profiles configured

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Summary by cubic

Fixes a React Rules of Hooks violation in ChatProfiles by moving both useEffect hooks above the early return so hook order stays stable as config loads. Prevents the "Rendered more hooks than during the previous render" error and keeps the component idle unless there are at least 2 profiles.

• Bug Fixes
  • Moved early return below the useEffect hooks to stabilize hook count.
  • Added optional chaining and guards in effects and deps to safely no-op when config.chatProfiles is missing or has 0–1 items.

^{Written for commit ecbf275. Summary will update on new commits.}