[Index / structure] bridgelet-product-audit/glossary/README.md: Glossary subfolder index

[phertyameen]

Index / structure: bridgelet-product-audit/glossary/README.md

Purpose:
Create an index file listing every glossary entry with a one-line summary and link.

This file should cover:

• Group entries thematically (wallet-connection terms, claim-flow terms, repository-structure terms).
• Keep each summary to one sentence, deferring full detail to the individual entry files.
• Note explicitly at the top that docs/GLOSSARY.md remains the canonical short-definition reference this subfolder expands on.

Scope: documentation-only addition to a new, standalone folder. No changes to frontend/ or mobile/ are needed to close this issue.

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Part of the bridgelet-product-audit/ knowledge-base initiative (95/100).