fix(ui): ignore code line anchors below 1, show JS errors in vite dev mode (#39432) (#40087)

Backport https://github.com/go-gitea/gitea/pull/39432

- A `#L0` URL hash made `selectRange` index the line list at -1 and
throw inside `initRepoCodeView`, which aborted every init function after
it on the page. Line numbers below 1 now select nothing.
- The JS error filter only accepted stacks under the asset prefix, but
the vite dev server serves the sources from `/web_src/`, so dev mode
dropped every error without showing a banner. Outside production, the
filter now also accepts stacks from `/web_src/`.

web_src/js/features/repo-code.ts

@@ -58,6 +58,7 @@ function selectRange(range: string): Element | null {
     stopLineNum = tmp;
     range = `${stop}-${start}`;
   }
+  if (startLineNum < 1) return null;
 
   const first = elLineNums[startLineNum - 1] ?? null;
   for (let i = startLineNum - 1; i <= stopLineNum - 1 && i < elLineNums.length; i++) {