Reintroduce Secondary TT Aging
Restricted secondary aging in TT to evict stale high-depth entries that could not cutoff.
Passed Non-regression STC:
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 189792 W: 48752 L: 48702 D: 92338
Ptnml(0-2): 428, 21147, 51711, 21167, 443
https://tests.stockfishchess.org/tests/view/69fae7b6c91f9625ce3253c8
Passed Non-regression LTC:
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 234792 W: 59743 L: 59741 D: 115308
Ptnml(0-2): 98, 24714, 67772, 24712, 100
https://tests.stockfishchess.org/tests/view/69ff3aa39392f0c317213e31
See #6742 for information and test results
```
Using ./stockfish_fix1 on KRvK_1000pv.epd with --nodes 1000000 --mate 0
Engine ID: Stockfish dev-20260505-1429d98e
Total FENs: 1000
Found mates: 620
Best mates: 159
Using ./stockfish_fix1 on KRvK_1000pv.epd with --nodes 10000000 --mate 0
Engine ID: Stockfish dev-20260505-1429d98e
Total FENs: 1000
Found mates: 1000
Best mates: 709
```
Closes #6576
Closes #6742
closes https://github.com/official-stockfish/Stockfish/pull/6818
Bench: 2821162