perf(config): increase OFFSET_SAMPLE_COUNT to 4 for higher success rate

Raises the default offset observation count from 3 to 4 to increase
the probability of successful chunk validation with early stopping.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <[email protected]>

Author: djwhitt

src/config.ts

@@ -165,7 +165,7 @@ export const OFFSET_OBSERVATION_SAMPLE_RATE = Math.max(
 
 export const OFFSET_SAMPLE_COUNT = +env.varOrDefault(
   'OFFSET_SAMPLE_COUNT',
-  '3',
+  '4',
 );
 
 export const OFFSET_OBSERVATION_ENFORCEMENT_ENABLED =