feat: add OSM node IDs to ExtractionSegment for Lua process_segment [wip]

[hamishcampbell]

Issue

No directly corresponding issue however this came about due to our inability to fix the bug here #7332

In the above issue we discovered problems while adjusting the speed of closed segments. We burned a week or two attempting to solve it without success however so we settled on modify the network at extract time as a much more reliable approach to setting road closure for large scale analysis.

To do this we need to be able to close specific segments but the process_segment function only exposed the lat/log of the relevant nodes. With this relatively minor change we can get access to the OSM source/target node IDs which are a stable ID vs attempting to use the coordinates themselves.

AI tools: Claude code assisted in generating this change, although with close human intervention/supervision.

Seeking comments on whether this is something that is generally useful before adding tests etc.

Change Summary

• Add osm_source_id and osm_target_id fields to ExtractionSegment struct
• Pass OSM node IDs during segment creation in extraction_containers
• Expose node IDs to Lua scripting environment

This allows profiles to:

• Create stable segment identifiers across runs
• Reference segments by OSM node pairs (e.g., 12345->67890)
• Load external segment-specific data by ID
• Pass routing changes by segment ID instead of coordinates

Tasklist

• self-review code for correctness and following the coding guidelines
• add tests (see testing)
• update relevant wiki pages
• review
• adjust for comments

Requirements / Relations

N/A