V-L2-C4: remove the wontfix tamper-evidence test (it asserts the bug)

[hyperpolymath]

Context

tests/integration_test.rs::test_provenance_chain_integrity_multi_step
contains an assertion that bakes in the current broken behaviour:

let mut tampered = update1.clone();
tampered.actor = "evil-mallory".to_string();
assert!(
    tampered.verify(),
    "Actor is not part of hash — tamper to actor alone is invisible"
);

Once V-L2-C1 lands and includes actor in the hash, this assertion
will fail (correctly). The test must be flipped — the new comment
should say "Actor IS part of the hash; tamper to actor breaks
verification."

What to do

After V-L2-C1 merges:

1. Delete the four lines quoted above.

2. Replace with:

   let mut tampered = update1.clone();
   tampered.actor = "evil-mallory".to_string();
   assert!(
       !tampered.verify(),
       "Tampering with actor must break verification"
   );

3. Verify cargo test is green.

Acceptance

• The wontfix assertion is gone
• Replacement asserts the correct (post-V-L2-C1) behaviour
• cargo test green