Unwrap scalar function arguments before type conversion

[JimmyLiuJia]

Fixes #1070.

String and numeric function literals remain wrapped values with Gson and the Jackson 2/3 JsonNode providers. concat($.one, "-", $.two) therefore returns one"-"two, while avg(1, 2) and index(1) discard their numeric arguments. Unwrap values at the argument consumption boundary before checking their type.

The regressions compile a separate query for each provider, avoiding reuse of another provider's cached function arguments, and include the original Jackson ReadContext example. Array parameters, boolean/null handling and appended JSON structures retain their existing behaviour.

Validation on Java 17 and 21 with Gradle 8.5: build --warning-mode all, check and clean publishToMavenLocal all pass. Each JDK's two-module suite runs 1,109 tests: 1,096 pass, 13 existing skips, no failures or errors. The same 83 regression cases have 13 failures on the original production source and all pass with this change, with no skips.

Scalar literal cases cover the seven providers that can parse scalar roots; array and structure cases cover all eight configurations. JSON-P's existing scalar-root parsing limitation is outside this fix.