Add TileModel#hasEgress

[Wezabi]

Set on Frac2 & Frac6. Might be helpful in the future but the point here was for new webUI to have access to this data point. See AsyncTI4/ti4_web_new#140

[github-actions]

🔬 Test Results

✅ JSON Validation Passed

All changed JSON files are valid.

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❌ Formatting Checks Failed

The following files have Spotless formatting violations:

• src/main/java/ti4/game/Tile.java

Fix: run mvn spotless:apply locally and commit the result.

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⏭️ JUnit Tests

Skipped — build failed at formatting checks (see above).