Conversion from string to numbers doesn't follow POSIX specification

[bertysentry]

Scalar variables in AWK can be either string, number or... strnum. See gawk's manual.

Conversion (especially in comparison and mathematical operations) is governed by these types as in the below table:

STRING	NUMERIC	STRNUM
STRING	string	string
NUMERIC	string	numeric
STRNUM	string	numeric

Jawk doesn't implement strnum and evaluates dynamically when to convert a String to a Number, and vice versa.

Consequence: the below script prints 1 with Jawk, while it should print 0 as with gawk:

BEGIN { r = 2 == "2.0"; print r }

More information can be found here (see the section "Expressions in awk")

[bertysentry]

Local implementation status from Codex workspace:

• Added an internal StrNum representation for input-derived numeric strings.
• Updated comparison semantics so plain strings force string comparison; Number/StrNum pairs compare numerically.
• Preserved permissive numeric-prefix conversion for arithmetic through JRT.toDouble.
• Added regression coverage for the reported examples, assignment preservation, concatenation producing plain strings, string literals, numeric operations, and hexadecimal input behavior.

Validation:

• mvn license:update-file-header formatter:format test passes: 430 tests, 0 failures, 14 skipped.
• mvn verify completes with BUILD SUCCESS and clean Checkstyle/PMD/SpotBugs. Existing compatibility reports still include unrelated unsupported gawk/BWK fixture failures; gawk strnum1, strnum2, and ofmtstrnum pass.