chore: remove Factorio module from public repo (Module Hub distribution)

Factorio is an optional add-on distributed via Module Hub, not part of
the core fleet. Remove 149 files (fleet/factorio/ + tests/factorio/)
from tracking. Files remain on disk for local development.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: SwiftWing21

.gitignore

@@ -146,10 +146,9 @@ BigEd/CONSOLE_UPGRADE_PLAN.md
 BigEd/SECURITY_COMPLIANCE_BLUEPRINT.md
 BigEd/research/
 
-# ── Factorio runtime data ─────────────────────────────────────────────────
-fleet/factorio/replay_log.jsonl
-fleet/factorio/server_data/
-fleet/factorio/checkpoints/
+# ── Factorio module (distributed via Module Hub, not in public repo) ──────
+fleet/factorio/
+tests/factorio/
 # ── Fleet runtime state ──────────────────────────────────────────────────
 fleet/hw_state.json
 fleet/tmp*.json
@@ -194,8 +193,6 @@ biged_audit.db
 biged_baseline.json
 .two-brain-audit.json
 
-# ── Fleet — learned packs (runtime RL output) ────────────────────────────────
-fleet/factorio/packs/learned/
 
 # ── Fleet — additional generated knowledge dirs ──────────────────────────────
 fleet/knowledge/digests/