chore(oracle): annotate two test-fixture strings to clear governance false-positive

src/oracle/src/lib.rs has two test fixtures that contain string
literals representing hardcoded secrets the oracle should *reject*:
  - line 732: password = "supersecretpassword123"
  - line 1051: const API_KEY = "abcdef1234567890abcdef"

The governance/secret-detector grep was matching these as real
secrets, but the secondary filter (grep -v
'example|sample|test|mock|placeholder') wasn't catching them because
the lines lacked any of those words.

Adding 'example test fixture' inline comments — single-line addition
each — so the filter excludes them. Semantics unchanged.

Author: hyperpolymath

src/oracle/src/lib.rs

@@ -729,6 +729,7 @@ mod tests {
             action_type: ActionType::CreateFile {
                 path: "config.rs".to_string(),
             },
+            // example test fixture: string the oracle should reject as a hardcoded secret
             content: r#"let password = "supersecretpassword123""#.to_string(),
             files_affected: vec!["config.rs".to_string()],
             llm_confidence: 0.9,
@@ -1048,6 +1049,7 @@ mod tests {
             action_type: ActionType::CreateFile {
                 path: "config.rs".to_string(),
             },
+            // example test fixture: string the oracle should reject as a hardcoded API key
             content: r#"const API_KEY = "abcdef1234567890abcdef""#.to_string(),
             files_affected: vec!["config.rs".to_string()],
             llm_confidence: 0.9,