Search all fields simultaneously

### Checks

- [x] I have read the Wiki, searched the open issues, and still think this is a new feature.

### Explain the problem clearly and succinctly:

Often I put information in the group title, entry title, notes or tags.

### Describe the solution you'd like:

It would be nice for the global free-form search to search all these fields in the same query free-form. Like KeePassXC. ` 2026` for example.

### Describe alternatives you've considered:

_No response_

### Additional context:

_No response_

Start at the global free-form search entry point and inspect how queries currently match group titles, entry titles, notes, and tags. Define how terms such as “part of note part of title part of tag 2026” should be interpreted, then add coverage showing that one query searches all four fields and returns the expected entries.

Written by the indexing model from the issue text.