fix: frontend component refactors, dead code cleanup, and docs update (#580, #581, #582, #583)

[SharifIbrahimDev]

Description

This Pull Request bundles fixes for frontend consistency, code cleanliness, and documentation accuracy in the FlowFi repository.

Closes

• closes [Frontend] Duplicated duration-unit-to-seconds constants (ScheduleStep vs lib/soroban) #580
• closes [Frontend] Remove commented-out dead code in WalletButton #581
• closes [Frontend] StreamCreationWizard shadows global 'timeout' with a state variable #582
• closes [Docs] README states Postgres on port 5432 but docker-compose maps 5433 #583

Changes Included

1. Duplicated duration-unit-to-seconds constants ([Frontend] Duplicated duration-unit-to-seconds constants (ScheduleStep vs lib/soroban) #580)

   • Exported a shared SECONDS_PER_UNIT map and DurationUnit type from frontend/src/lib/soroban.ts.
   • Refactored ScheduleStep.tsx to use the shared constants instead of inline magic numbers and switch statements for calculating totalSeconds.
   • Ensures the wizard rate previews align perfectly with the submitted duration.

2. Dead code in WalletButton ([Frontend] Remove commented-out dead code in WalletButton #581)

   • Cleaned up WalletButton.tsx by removing the commented-out networkLabel logic and the abandoned wallet-chip__name / wallet-chip__network markup.
   • Preserved the network-mismatch warning in the dropdown exactly as requested.

3. Global timeout shadowing ([Frontend] StreamCreationWizard shadows global 'timeout' with a state variable #582)

   • Renamed the timeout state variable in StreamCreationWizard.tsx to timeoutError to prevent shadowing the global timeout function.
   • Adjusted all corresponding JSX branches ({timeoutError ? ... : ...}).
   • Ensures no behavior change while vastly improving readability alongside the existing setTimeout calls in the polling function.

4. Postgres Port Mismatch in Docs ([Docs] README states Postgres on port 5432 but docker-compose maps 5433 #583)

   • Updated README.md to state the correct host port 5433 (matching the docker-compose.yml mapping).
   • Updated backend/.env.example to point the DATABASE_URL and SANDBOX_DATABASE_URL examples to localhost:5433.

Verification

• Duration calculations work correctly across the stream creation wizard and Soroban interactions.
• WalletButton.tsx is cleaner and maintains full expected functionality.
• Polling in StreamCreationWizard.tsx continues to work properly and the code is clearer.
• The repository documentation is now aligned perfectly with the actual docker compose configuration, eliminating setup confusion for new contributors.