CAMEL-22894: extract math and string Simple functions into dedicated factories

[ammachado]

Description

Extract Simple language math and string functions from the monolithic SimpleFunctionExpression into dedicated SimpleLanguageFunctionFactory implementations, continuing the refactoring started in #23382.

• MathFunctionFactory: handles abs, floor, ceil, sum, max, min, average (both expression and CSimple code-gen paths)
• StringFunctionFactory: handles replace, substring, substringBefore, substringAfter, substringBetween, contains, trim, val, capitalize, pad, concat, quote, safeQuote, unquote, uppercase, lowercase, length, size, normalizeWhitespace (both paths)
• Consolidates the full codeSplitSafe implementation into SimpleFunctionHelper, deprecating the delegation stub on SimpleFunctionExpression
• Both factories are registered in SimpleFunctionDispatcher.BUILT_INS
• Reduces SimpleFunctionExpression from ~3600 to ~2300 lines

Documentation fixes (simple-language.adoc)

• Clarified substring(num1,num2) and substring(num1,num2,exp) table descriptions: explicitly states that num1 clips from the beginning and num2 clips from the ending.
• Fixed mismatched backtick/parenthesis in contains(text), contains(exp,text), and iif(predicate,trueExp,falseExp) table entries.
• Added missing closing parentheses in substringBetween(after,before) and substringBetween(exp,after,before) table entries.
• Fixed isAlpha() and isAlpha(exp) descriptions: changed "numeric value" to "alphabetic value".

Claude Code on behalf of Adriano Machado

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🤖 Generated with Claude Code

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🧪 CI tested the following changed modules:

• core/camel-core-languages
• core/camel-core

ℹ️ Dependent modules were not tested because the total number of affected modules exceeded the threshold (50). Use the test-dependents label to force testing all dependents.

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Build reactor — dependencies compiled but only changed modules were tested (2 modules)

• Camel :: Core
• Camel :: Core Languages

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