Fix/fast axis

[wakonig]

This PR fixes inconsistencies in BEC where the fast axis was not always the inner axis. Moreover, the trajectory optimization simply ignored the convention.

[Copilot]

Pull request overview

This PR standardizes the “fast axis is the inner axis” convention across scans and updates corridor trajectory optimization so it no longer ignores that convention, adding regression coverage to lock in the intended ordering/direction behavior.

Changes:

• Update corridor optimization to use fast_axis, first_corridor_direction, and snaked to control ordering and traversal direction.
• Adapt scan components (and Fermat/hex scans) to pass the new corridor-optimization parameters consistently with the fast-axis convention.
• Add/adjust tests to verify fast-axis ordering and corridor snaking/direction behavior.

Reviewed changes

Copilot reviewed 10 out of 10 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
bec_server/bec_server/scan_server/path_optimization.py	Refactors corridor optimizer API/logic to be fast-axis driven and adds Direction enum support.
bec_server/bec_server/scan_server/scans/scan_components.py	Updates optimize_trajectory() corridor dispatch to the new corridor optimizer API.
bec_server/bec_server/scan_server/scans/position_generators.py	Adjusts hex grid generation semantics to treat axis1 as the fast axis.
bec_server/bec_server/scan_server/scans/legacy_scans.py	Aligns legacy corridor optimization call sites and hex grid docs/axis semantics; introduces first_direction on legacy Fermat scan.
bec_server/bec_server/scan_server/scans/fermat_scan.py	Applies trajectory optimization in v4 Fermat scan using the new first-corridor direction convention.
bec_server/tests/tests_scan_server/test_path_optimization.py	Adds regression test ensuring first_corridor_direction and snaked are respected.
bec_server/tests/tests_scan_server/test_legacy_scans.py	Updates hex scan snaking test parameters to match axis semantics.
bec_server/tests/tests_scan_server/scans_v4/test_scan_components.py	Updates corridor optimization expectations and adds coverage for new parameter passing.
bec_server/tests/tests_scan_server/scans_v4/test_hexagonal_scan.py	Adds coverage asserting second axis is treated as fast axis.
bec_server/tests/tests_scan_server/scans_v4/test_fermat_scan.py	Adds coverage for Fermat corridor first-direction selection based on fast-axis range.

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

[codecov]

Codecov Report

❌ Patch coverage is 93.75000% with 3 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
...server/bec_server/scan_server/path_optimization.py	84.61%	1 Missing and 1 partial ⚠️
...erver/bec_server/scan_server/scans/legacy_scans.py	92.30%	1 Missing ⚠️

📢 Thoughts on this report? Let us know!