#563: Extract tag importer into shared module

[kaklakariada]

Part of #563

Summary

• Extract the tag importer's reusable parsing infrastructure into the new importer/tag-importer-common module, including line reading, regex consumption, full-tag parsing, and long/short tag consumers.
• Update the tag importer to use the shared parser and remove the moved local implementations.
• Wire the new module into Maven and JPMS metadata, and include it in the self-trace workflow.
• Add and relocate unit tests for the shared module, including parameterized long- and short-tag tests and complete LineReader path coverage.
• Add the Support Gherkin .feature files as OpenFastTrace specification documents #563 implementation plan and harden GitHub Actions by disabling persisted Git credentials.
• Remove the obsolete VS Code setting.

Verification

• Focused Maven tests for the shared tag importer module
• ./oft-self-trace.sh

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
96.9% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud