Wallet provider compatibility matrix and fallback routing

[Kalebtron1]

Why this matters

Contributors need to know which wallet works in which environment.

Problem

The supported wallet matrix and fallback order are not documented clearly enough.

Scope

• Document which wallets work on mobile and desktop.
• Describe the fallback routing order.
• Clarify what happens when a provider is unavailable.

Setup Steps

• Clone the repository and review the wallet docs locally.
• Run npm run dev and compare the login flow across device sizes.
• Run npm run build if the doc change touches bundled pages.

File Paths

• src/lib/mobileWalletConnectors.ts
• src/wallet/index.ts
• src/components/WalletSetupModal.tsx
• README.md
• PR_TEST_CHECKLIST.md

Implementation guidance

• Document the compatibility matrix and fallback order in the repo.
• Keep the matrix aligned with the actual code paths.
• Reference the real providers already supported by the app.

Acceptance criteria

• PR documents the active wallet options and fallback behavior.
• Reviewer can tell which wallet should be used on each device type.
• The PR description notes any unsupported combinations.

Validation

• Review the matrix against the current wallet code.
• Confirm the documented behavior matches the actual login flow.

PR requirements

• Include Closes #76.
• Include before/after behavior notes.

Complexity

• Trivial (50 points)

[Olasunkanmi975]

@Olasunkanmi975 has applied to work on this issue as part of the Stellar Wave Program's 6th wave.

I am ready to review the codebase, isolate the flaw, and deliver a clean, well-documented solution.

ℹ️ Repo Maintainers: To accept this application, review their application or assign @Olasunkanmi975 to this issue.