System loads mirrored version of sence/antisence chain if opened as new project

**Steps to Reproduce**
1. Open Ketcher (or reload it if already opened)
2. Go to Macromolecules - Flex mode <-- IMPORTANT!
3. Load from HELM using `Open as new` button: `RNA1{([25mo3r],[25R])(A,C,G,T,U)([gly],[hn]).R(A)P.([25mo3r],[25R])(A,C,G,T,U)([gly],[hn]).R(A)P.([25mo3r],[25R])(A,C,G,T,U)}|RNA2{([25mo3r],[25R])(A,C,G,T,U)([gly],[hn]).R(A)P.([25mo3r],[25R])(A,C,G,T,U)([gly],[hn]).R(A)P.([25mo3r],[25R])(A,C,G,T,U)}|PEPTIDE1{A}$RNA1,RNA2,2:pair-14:pair|RNA1,RNA2,14:pair-2:pair|RNA1,RNA2,8:pair-8:pair|RNA1,RNA2,5:pair-11:pair|RNA1,RNA2,11:pair-5:pair|RNA1,PEPTIDE1,13:R2-1:R1$$$V2.0`

**Actual behavior**
System loads chain in mirrored view

**Expected behavior**
System loads chain correct

**Versions**
- Ketcher Version 3.18.0-rc.1 Build at 2026-07-21; 19:39:52
- Indigo Version 1.46.0-rc.1.0-gf3408986b-wasm32-wasm-clang-23.0.0
- Chrome Version 150.0.7871.125 (Official Build) (64-bit)
- Win10

Related issue - https://github.com/epam/ketcher/issues/3222

Reproduce the issue in Ketcher’s Macromolecules - Flex mode using the supplied HELM string and the Open as new action. Compare the mirrored result with the expected image, then review the related issue #3222 and linked pull request #10831 for prior investigation. Done means the chain loads in the expected orientation.

Written by the indexing model from the issue text.