fix(preview): a shell prompt's trailing $ or # stays out of its folder link (#604 merge-time fix)

The folder link pattern treats `:` as a boundary and allows `$`/`#` in a path,
so every default bash prompt (`user@host:~/proj$`, `root@c:/workspace#`)
became a folder link to a path that does not exist, and clicking it showed
"Folder not found". folderLinkPath now strips them, so the link opens the
prompt's cwd.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

test/file-path-link-forms.test.ts

@@ -90,6 +90,11 @@ describe('findFilePathLinks', () => {
     expect(paths('see src/a.ts:120.')).toEqual(['src/a.ts']);
   });
 
+  it("keeps a shell prompt's trailing `$` or `#` out of the folder it links", () => {
+    expect(paths('arkon@tnode:~/default/claudeman$ ls')).toEqual(['~/default/claudeman']);
+    expect(paths('root@c:/workspace/app# ls')).toEqual(['/workspace/app']);
+  });
+
   it('still finds rooted absolute paths, and never a relative path inside one', () => {
     expect(paths('sign-off from /mnt/raid1/x/refs/look_montage.png.')).toEqual(['/mnt/raid1/x/refs/look_montage.png']);
     // Unknown root: not linked at all (no `nix/store/…` cut out of it).