[Contracts][Bug] panic!()/unwrap() in production contract code paths

[Penielka]

Overview

Several production (non-test) contract files panic or unwrap on data that may legitimately be absent:

• contracts/src/access_control.rs:79-82 — panic!("Caller does not have Admin role") etc. instead of returning an error (reverts burn all gas for the caller)
• contracts/src/access_control.rs:34,53,68 — roles.get(i).unwrap()
• contracts/src/analyticsStorage.rs:71,107,134,148,187-188,203 — unwrap() on vector indexing

In Soroban, panics revert the transaction and waste the entire submission fee; a panic in an admin-check path also bricks governance operations for everyone. Unwraps on Vec::get should be require!(...) or ok_or(...)? with clear error codes.

Evidence

• contracts/src/access_control.rs — panics in require_role-style logic
• contracts/src/analyticsStorage.rs — multiple .unwrap()

Acceptance Criteria

• Replace panics in role checks with require!/error returns (or #[contracterror] variants)
• Replace .unwrap() on vector lookups with checked access and contract errors
• Add tests asserting error paths return proper Err instead of panicking

Files to Modify

• contracts/src/access_control.rs
• contracts/src/analyticsStorage.rs

Priority: High