Support the logical not operator in profile activation conditions

[SEPURI-SAI-KRISHNA]

Fixes #12736

What

Adds handling for the ! operator to ConditionParser.parseUnary().

Why

The tokenizer already treats ! as an operator and emits a bare ! token, but no parser rule
consumes it. Writing the natural form of a negated condition:

<condition>!exists('some/path')</condition>

fails with Unknown variable: !, which is confusing — nothing in the expression is a variable.

! is defined here as sugar for the not() function that already exists, using the same
toBoolean() coercion, so this adds no new capability and no new semantics. It is handled in
parseUnary(), giving it the same precedence as in Java: tighter than arithmetic, comparison,
&& and ||.

!= is unaffected — the tokenizer emits it as a single token before a bare ! can be produced.

Tests

Four tests added to ConditionParserTest, all failing before the change:

• testLogicalNotOperator — basic negation, stacking (!!, !!!), and negating a function call
• testLogicalNotOperatorMatchesNotFunction — pins !x to the same result as not(x)
• testLogicalNotOperatorPrecedence — precedence against &&, || and parenthesised groups
• testLogicalNotOperatorCoercion — string/number coercion matches not()

The negation tests deliberately use contains('Hello, World!', ..), which puts a ! inside a
string literal, to confirm the tokenizer still leaves quoted ! alone.

---

Out of scope — a separate bug found while testing this

compare() handles Number vs Number and String vs String, but has no Boolean branch, so
comparing two booleans throws on the unmodified parser:

true == true    => RuntimeException: Cannot compare true and true with operator ==
true != false   => RuntimeException: Cannot compare true and false with operator !=

This is pre-existing and independent of !. It is deliberately NOT fixed in this PR, and the
tests here avoid boolean-to-boolean comparison. Candidate for a fourth PR.

---

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[gnodet]

Clean, well-implemented addition of the logical ! operator to the ConditionParser. The implementation correctly mirrors the existing not() function by calling the same toBoolean() coercion, and the recursive parseUnary() call naturally supports stacking (!!, !!!).

The placement in parseUnary() gives ! the expected Java-like precedence (tighter than arithmetic, comparison, &&, and ||), and the tokenizer already correctly emits != as a single token before a bare ! can be produced, so no regression is possible there.

The four new test methods provide strong coverage of basic negation, equivalence with not(), precedence interactions, and type coercion. Nice touch using contains('Hello, World!', ...) to exercise ! inside string literals.

Minor nit: testNotEqualsStillParsesAsOneOperator is redundant with existing assertions in testStringComparison and testArithmeticComparisons, though it serves as a self-documenting regression guard for this change.

Thorough PR description with correct scoping — the pre-existing compare() issue is correctly identified as out of scope.

This review was generated by an AI agent and may contain inaccuracies. Please verify all suggestions before applying.

Claude Code on behalf of gnodet