Monomers with hyphens in names are loaded incorrectly

Found while testing #3541

**Steps to Reproduce:**

1. Open Macromolecules - Flex mode (clean canvas)
2. Paste the following BILN string from the clipboard: `[D-2Thi]-[D-gGlu]-[Lys-al]`
3. Click `Open as New` or `Add to Canvas` button

**Actual Result:**
System treats hyphens within the square brackets as monomer connections and loads 6 monomers with incorrect names instead of 3 monomers that contain hyphens in their names

**Expected Result:**
The system should correctly interpret monomer names containing hyphens and load three monomers with the names: `D-2Thi`,` D-gGlu`, and `Lys-al`

**Found in Environment:**

- Ketcher Version 3.17.0-rc.1 Build at 2026-06-02; 21:27:10
- Indigo Version 1.45.0-rc.2.0-g168fb85f2-wasm32-wasm-clang-23.0.0
- Chrome Version 149.0.7827.156 (Official Build) (64-bit)
- Win11

Reproduce the BILN input [D-2Thi]-[D-gGlu]-[Lys-al] in Macromolecules Flex mode using Open as New or Add to Canvas, then trace the BILN loading path in Indigo. Add a regression test showing that the input produces three monomers with hyphens in their names rather than six connected monomers.

Written by the indexing model from the issue text.