Fix Chase Qfx File Type Selector

1. Implementation

• 1.1 Share the Chase QFX file-type selector family between form-load wait and file-type selection.
• 1.2 Add a semantic fallback for the Chase file-type combobox.
• 1.3 Add a regression test for the shared selector family.

2. Validation

• 2.1 Run openspec validate fix-chase-qfx-file-type-selector --strict.
• 2.2 Run focused Chase connector tests.
• 2.3 Run polyfill connector typecheck.
• 2.4 Run owner-mediated live Chase retry after deploy before declaring the live gap closed.