[Codebase Audit] Reduce panic-prone calls in `src/kyc/provider.rs`

[kelly-musk]

Problem

src/kyc/provider.rs contains 18 panic-prone calls (unwrap, expect, or panic!).

Evidence

• src/kyc/provider.rs:199 — .expect("Failed to create HTTP client");
• src/kyc/provider.rs:211 — .expect("Invalid key length");
• src/kyc/provider.rs:259 — session_id: result["session_id"].as_str().unwrap().to_string(),
• src/kyc/provider.rs:261 — expires_at: DateTime::parse_from_rfc3339(result["expires_at"].as_str().unwrap())
• src/kyc/provider.rs:262 — .unwrap()

Proposed fix

Replace non-essential unwrap/expect usages with typed error propagation and contextual logging. Keep explicit panics only where unrecoverable invariants are well-documented.

Acceptance criteria

• All avoidable panic-prone calls in this file are removed or justified with comments/tests.
• Error paths return typed errors and preserve observability context.
• Existing tests pass (or new tests cover changed paths).

[Toyinoje]

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

Hello maintainer, i will like to work on this issue

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