This PR addresses four test improvements across the Soroban contracts and NestJS backend. - #1304

Summary

This PR addresses four test improvements across the Soroban contracts and NestJS backend. It adds a comprehensive full-lifecycle integration test for the earnings contract, verifies WASM builds in CI for
the test-consumer contract, introduces property-based invariant tests to catch edge cases, and completes controller unit tests with mocked services for the creators module.

Changes

#987 — Full lifecycle integration test via test-consumer

• Added test_integration_full_lifecycle to earnings_integration test module
• Tests complete workflow: initialize → record earnings → get balance → withdraw
• Verifies state consistency after each step
• Ensures multiple creators maintain independent balances
• Confirms final state correctness (no funds leak, balances sum correctly)

#988 — WASM build verification for test-consumer in CI

• Added wasm release build step for test-consumer contract to CI workflow
• Follows exact same pattern as existing earnings contract build
• Verifies test_consumer.wasm artifact builds cleanly
• Includes comment explaining why wasm build is necessary (cargo test uses host target)
• Prevents wasm-only build errors from slipping through CI

#989 — Property-based invariant tests for test-consumer

• Added proptest v1 as dev-dependency with std feature
• Implemented prop_invariant_balance_conservation: verifies that for any sequence of records and withdrawals, final balance = recorded - withdrawn, and balance >= 0
• Implemented prop_invariant_read_function_idempotency: verifies that calling read-only functions (admin(), get_earnings()) twice returns identical results and doesn't change state
• Both tests use proptest strategies to generate arbitrary valid amounts
• Each iteration creates fresh Env to prevent state bleed between test cases

#990 — Creators controller unit tests with mocked service

• Expanded creators.controller.spec.ts to cover all controller methods
• Added tests for createPlan: valid input, invalid input scenarios
• Added tests for getAllPlans: paginated results, empty results
• Added tests for getPlans: creator with/without plans
• Added tests for getDashboard: with query parameters, not-found error handling
• Uses jest.fn() mocking pattern consistent with existing tests
• Overrides JwtAuthGuard to isolate controller logic

Notes

• Full lifecycle test determined from earnings contract lib.rs: init → record → get_earnings → withdraw
• test-consumer package name confirmed from Cargo.toml, crate name test_consumer for .wasm artifact
• proptest crate added (no existing fuzz testing dependency found)
• Controller mock service pattern matched from existing test file setup
• All controller methods confirmed from creators.controller.ts decorator routes
• No co-author tags added to commits per requirement

Closes #987, Closes #988, Closes #989, Closes #990