Clockwork dev-20260425-7c902757

Add better SE guards (#393)

Passed STC nonregr:
```
Test  | semateguard
Elo   | 2.42 +- 2.74 (95%)
SPRT  | 8.0+0.08s Threads=1 Hash=16MB
LLR   | 2.95 (-2.94, 2.94) [-3.00, 0.00]
Games | N: 20996 W: 5464 L: 5318 D: 10214
Penta | [251, 2484, 4888, 2618, 257]
```
https://ob.cwchess.org/test/1382/

Passed LTC nonregr:
```
Test  | semateguard
Elo   | 3.17 +- 2.80 (95%)
SPRT  | 40.0+0.40s Threads=1 Hash=64MB
LLR   | 3.07 (-2.94, 2.94) [-3.00, 0.00]
Games | N: 16466 W: 4064 L: 3914 D: 8488
Penta | [68, 1923, 4126, 2023, 93]
```
https://ob.cwchess.org/test/1384/

Bench: 15544260