fix(kotlin): read a function's signature positionally (#1495) (#1807)

Land upstream PR #1687 by danusha2345 (fix commit 6e9bbb26), using the
PR tip implementation with only a Rust doc-comment placement cleanup.

Read parameter lists and return types positionally in the wasm extractor
and native kernel in lockstep, preserving verbatim signature text.

Verified on Linux x64 with Node 22.19.0: reproduced three undefined
signatures in both backends before the fix, then confirmed all three
expected signatures and exact wasm/kernel parity after rebuilding
TypeScript and the linux-x64 kernel. All 31 focused tests pass: 15 Kotlin
extraction, 6 Kotlin parity, and 10 kernel scaffold checks, with
CODEGRAPH_KERNEL_EXPECT=1 for the native suites.

Add the upstream #1495 changelog bullet while preserving all other
Unreleased entries. Keep EXTRACTION_VERSION unchanged for this bug fix.

Co-authored-by: Colby McHenry <colbymchenry@users.noreply.github.com>

CHANGELOG.md

@@ -233,6 +233,7 @@ and adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
 #### Symbols, tests and the viewer
 
+- Kotlin functions and methods now carry their signature — `(params): ReturnType` — in `codegraph_explore`, `node` and the viewer, instead of no signature at all. Re-index Kotlin projects after upgrading. (#1495)
 - `codegraph affected` now finds Go, Python and JVM test files that previously went unreported, while preserving custom `--filter` behavior (thanks @danusha2345; #1507, #1688).
 
 - Calls inside declaration initializers in Kotlin, Java, TypeScript, JavaScript, Scala, Rust and Python now appear under the declaration that owns them, making callers and impact results more accurate after re-indexing with `codegraph index -f` (thanks @danusha2345; #1510, #1511).