[Depo-dev]

Adds four docs, one per issue:

• docs/flows/token-transfer.md (closes Flow docs: in-chat token transfers end to end #636)
• contracts/docs/tutorial-testnet-treasury.md (closes Tutorial: create and run a group treasury on testnet #634)
• apps/backend/docs/howto-add-rest-endpoint.md (closes How-to: add a new REST endpoint end-to-end #617)
• apps/web/docs/crypto-module-map.md (closes Client crypto module map #624)

The testnet tutorial was run on testnet with stellar 25.2.0. Where the issue text and the code disagree, the docs describe the code and say so:

• group_treasury has no execute entrypoint; reaching the threshold only sets Passed.
• deploy_group_treasury.sh fails on testnet (wasm target, missing --threshold, invalid keys flag); the tutorial works around it by hand and the script is not changed here.
• No NEXT_PUBLIC_* variable exists for the group treasury contract.
• The in-chat transfer flow has no UI trigger and no client call to POST /transfers on dev.
• The live crypto send and receive paths do not currently interoperate.

Unmounted audit-logs route filed separately: #648

[drips-wave]

@Depo-dev Great news! 🎉 Based on an automated assessment of this PR, the linked Wave issue(s) no longer count against your application limits.

You can now already apply to more issues while waiting for a review of this PR. Keep up the great work! 🚀

Learn more about application limits