Fix broken README link and React panel apostrophe

[hamedrabah]

Summary

• fix the malformed FlexSearch link in the README
• replace the literal Unicode escape on the React panel page with a renderable apostrophe

Validation

• git diff --check
• targeted assertions confirm the corrected link and apostrophe are present and the malformed forms are absent

Closes #232
Closes #234

[vercel]

@hamedrabah is attempting to deploy a commit to the Replay Team on Vercel.

A member of the Team first needs to authorize it.

[hamedrabah]

@striderwilsonreplay when you have a chance, could you take a look? This is a small docs-only fix for #232 and #234. Thanks!

[hamedrabah]

@jasonLaster, could you review this fix for #232 and #234 and authorize the Vercel preview when convenient? The remaining failed status is the Vercel authorization gate for an external contributor.