Implement GF-17 trust and info pages

[ashalafan]

Summary

• Add /learn, /faq, /audit, /contracts, and /roadmap trust pages.
• Link the new pages from the landing page footer.
• Add shared responsive info-page styling plus a contracts network toggle.

Acceptance coverage

• /learn includes a worked 100 USDC share-unit example for Flex vs 12-month locks.
• /faq uses native expandable accordion items.
• /audit surfaces the internal audit findings and resolution commits from the repo report.
• /contracts shows testnet deployment entries with Stellar Expert links and mainnet pending status.
• /roadmap reflects the current pre-mainnet state and launch gates.

Verification

• .\node_modules.bin\tsc.cmd --noEmit
• .\node_modules.bin\next.cmd build

Build passes. Existing lint warnings remain in CompoundChart.tsx and useAPY.ts outside this change.

Closes #49

[vercel]

@ashalafan is attempting to deploy a commit to the wumibals' projects Team on Vercel.

A member of the Team first needs to authorize it.