fix(explore): reliably pin extension-less kebab-case file basenames in queries

Previously, naming a kebab-case file without its extension (e.g., `background-image-table` vs. `background-image-table.tsx`) in a `codegraph_explore` query would shred the name into fragments (`background`, `image`, `table`), admitting irrelevant sibling files and crowding out the intended target.

This change introduces a new resolution pass in `extractQueryPaths` specifically for extension-less kebab basenames. Queries now accurately identify and pin these files. Unresolved hyphenated prose (e.g., `cross-call`) is left in the query for FTS without being flagged as an unknown path. Resolution prioritizes explicit slashed/dotted paths and respects an ambiguity budget for common stems to prevent over-pinning.

__tests__/fixtures/explore-path-pinning/src/lib/background-image-table.ts

@@ -0,0 +1,21 @@
+/** Table of background images for a training set — source-column rendering. */
+
+export interface BackgroundImageRow {
+  id: string;
+  sourceUrl: string;
+  label: string;
+}
+
+let tableRows: BackgroundImageRow[] = [];
+
+export function loadTableRows(rows: BackgroundImageRow[]): void {
+  tableRows = rows;
+}
+
+export function renderSourceColumn(row: BackgroundImageRow): string {
+  return `${row.label}: ${row.sourceUrl}`;
+}
+
+export function sortRowsBySource(): BackgroundImageRow[] {
+  return [...tableRows].sort((a, b) => a.sourceUrl.localeCompare(b.sourceUrl));
+}

__tests__/fixtures/explore-path-pinning/src/lib/background-store.ts

@@ -0,0 +1,11 @@
+/** Uploaded-background registry — shares the `background` fragment with the table file. */
+
+let backgrounds: string[] = [];
+
+export function addBackground(url: string): void {
+  backgrounds.push(url);
+}
+
+export function listBackgrounds(): string[] {
+  return [...backgrounds];
+}