fix(extraction): index const-bound functions inside a body as symbols (#1669) (#1774)

`const handleClear = () => {…}` inside a component — every React handler
that skips useCallback — was never a symbol: the body walker only named
nested function declarations and hook-bound arrows, so the handler was
absent from callers/impact ("Symbol not found", indistinguishable from
"no callers") and its calls attributed to the component. Bind the arrow
or function expression to its declarator the way module scope already
does, in both the wasm walker and the kernel.

A navigation such a handler makes is now the handler's own edge and a hop
in the Screens `via` chain — the shape a useCallback handler already has —
so the react-router and expo-router expectations follow that convention.

Co-authored-by: danusha2345 <ewidusoc498@gmail.com>
Co-authored-by: Colby McHenry <colbymchenry@users.noreply.github.com>

CHANGELOG.md

@@ -213,6 +213,7 @@ and adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
 #### Symbols, tests and the viewer
 
+- **Functions bound with `const` inside another function are symbols now.** `const handleClear = () => {…}` inside a React component — every handler that skips `useCallback` — was invisible to `callers`, `callees` and impact, answering "Symbol not found" exactly the way a function with no callers would. It is indexed like its module-level twin, contained by the enclosing function, with its own calls. Re-index after upgrading. (#1669)
 - `codegraph callers`, `callees`, and `query` now clearly report when their result limit hides additional matches, including exact totals in callers/callees JSON output; the `codegraph_callers` and `codegraph_callees` MCP answers carry the same "showing N of M" note. (#1639, #1674)
 - CommonJS controllers written as `exports.getItems = async (req, res) => {…}` or `module.exports.x = function () {…}` are now indexed as exported functions, so `node`, `callers` and impact find every Express handler in that style and the calls inside them belong to the handler instead of the file. Re-index JavaScript projects after upgrading. (#1675)
 - Python parameters annotated with a quoted forward reference — `def f(o: "Alpha")`, or anything under `from __future__ import annotations` — now resolve the methods called on them, the same as the unquoted annotation. Re-index Python projects after upgrading. (#1684)