Configure [[test]] entries so unit/integration tests are compiled by Cargo

[DeFiVC]

What

Test files in tests/unit/ and tests/integration/ subdirectories are never compiled because Cargo only auto-discovers integration tests at the top level of tests/. None of the bugs in those files are caught by cargo test.

Why

All bugs found in progress_tests.rs, credential_flow.rs, and token_tests.rs are invisible to the CI pipeline — these files exist but are silently skipped during compilation. This means the test suite gives a false sense of coverage.

Scope

• Add [[test]] entries to the workspace Cargo.toml for each test file in subdirectories
• Alternatively, restructure to use a tests/main.rs module root
• Verify all tests are now compiled and discovered by cargo test

Technical Context

• File: Cargo.toml (workspace root)
• Test files: tests/unit/token_tests.rs, tests/unit/progress_tests.rs, tests/unit/credential_tests.rs, tests/integration/credential_flow.rs
• Cargo's default behavior only auto-discovers tests/*.rs (flat), not tests/**/*.rs

Acceptance Criteria

• cargo test compiles and runs all test files in subdirectories
• Each test file is discoverable (run cargo test -- --list to verify)
• No duplicate test names across entries

[EstherIkechukwu]

I have gone through the description expect a pr in less than 12hrs

[odiliflash-ops]

I would love to work on this issue