fix(security): remove input length cap from regex validation

The 10k character cap would block legitimate guardrail checks on long
LLM outputs. Input length doesn't affect ReDoS risk — the safe-regex2
pattern check already prevents catastrophic backtracking.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: waleedlatif1

apps/sim/lib/guardrails/validate_regex.ts

@@ -1,7 +1,5 @@
 import safe from 'safe-regex2'
 
-const MAX_INPUT_LENGTH = 10_000
-
 /**
  * Validate if input matches regex pattern
  */
@@ -25,13 +23,6 @@ export function validateRegex(inputStr: string, pattern: string): ValidationResu
     }
   }
 
-  if (inputStr.length > MAX_INPUT_LENGTH) {
-    return {
-      passed: false,
-      error: `Input exceeds maximum length of ${MAX_INPUT_LENGTH} characters`,
-    }
-  }
-
   const match = regex.test(inputStr)
   if (match) {
     return { passed: true }