fix(engine): gate a reflexive "when you do" on the optional action actually happening - #7414

Scan completed for PR #7414 (head: 5e19b92).

Files reviewed (5):

• crates/engine/src/game/effects/mod.rs
• crates/engine/src/types/ability.rs
• crates/engine/tests/integration/issue_1328_inti.rs
• crates/engine/tests/integration/main.rs
• crates/engine/tests/integration/skitterfang_reflexive_without_counter.rs

Areas checked:

1. CI/CD changes — none present.
2. Lifecycle events — no build scripts, package hooks, or runtime entrypoints modified.
3. Malicious intent — no secret exfiltration, obfuscation, encoded payloads, network calls, credential handling, suspicious binaries, eval/exec patterns, or behavior-hiding changes detected.
4. Skill mutations — no materialized skill target directories to scan.

This PR is a rules-engine bugfix for Magic: The Gathering reflexive triggers. All changes are well-documented Rust source and test additions matching the described fix.