fix(lsp): suggest import map aliases in auto-imports for local directories (#33048)
## Summary
- When an import map defines a meaningful alias like `"@app/":
"./src/"`, auto-import completions now correctly suggest the alias
(e.g., `@app/islands/components/Button.tsx`) instead of only offering
relative paths (e.g., `../../islands/components/Button.tsx`).
- The `import_map_lookup` function was skipping import map entries
whenever the referrer file was inside the mapped directory. This
narrowed the skip condition to only apply to passthrough mappings (e.g.,
`"src/": "./src/"`) where the key matches the last path segment of the
resolved address.
Fixes #32288
Fixes #31590
---------
Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>