[Feature]: Support multi-term path filtering in Quick Open

### Problem or use case

In monorepos, repeated filenames such as `.env` produce many Quick Open results. Today, adding a folder term such as `.env api` does not narrow the list to `apps/api/.env`, because the full input is treated as one fuzzy sequence. This makes locating common filenames slower in both Quick Open and the tab-bar file picker.

### Proposed solution

Treat whitespace as separating independent fuzzy terms. Require every unique term to match the normalized relative path, regardless of term order, while retaining the existing filename ranking bonuses and single-term behavior.

Examples:

- `.env api` matches `apps/api/.env`
- `api .env` produces the same match
- mixed whitespace and duplicate terms behave consistently

Apply the same matching behavior to Quick Open and the tab-bar file picker. Keep input work bounded by the existing 2 KiB query limit plus a 32-unique-term limit.

### Alternatives or additional context

Typing a longer path fragment works when the exact directory layout is known, but it is less convenient and does not provide VS Code-style filename-plus-folder filtering. I have an implementation with regression tests ready and will open a linked draft PR immediately.