Associate Tag filter label with its input

[schiste]

Follow-up from PR #84 review thread.

Codex noted that the filter bar refactor leaves the visible Tag: text as a standalone text primitive while the TextInput has neither a matching Field/for association nor an aria-label.

Impact:

• Clicking Tag: no longer focuses the textbox.
• Assistive tech does not get the visible label for the Tag filter control.

Suggested fix:

• Wrap the Tag filter input in the shared Field primitive, matching the select controls, or provide an explicit accessible label through the shared input API.

Source: PR #84 review thread PRRT_kwDORwcFgc6NkrA3.