Preserve camera direction range spans

[anthony-maio]

Summary

Preserves the width of OSM direction ranges so downstream camera maps can render the documented field of view instead of reducing every range to its midpoint.

Root Cause

data/cameras/lib.mjs parsed ranges such as 239-284 into a midpoint but discarded the original 45-degree span. That made the GeoJSON and generated PMTiles indistinguishable from a single-bearing camera.

Execution Flow

flowchart LR
    A[OSM direction range] --> B[Camera parser]
    B --> C[Hourly GeoJSON]
    C --> D[Main and filtered PMTiles]
    D --> E[Maps renderer]

Loading

Fix

• Publish optional directionSpan for the first retained direction token.
• Publish index-aligned directionSpans for plural directions when at least one token is a range.
• Preserve null placeholders for non-range entries without inventing all-null metadata.
• Keep the existing direction and directions fields unchanged for compatibility.
• Bump the camera tile build token to v9-direction-spans so archives rebuild with the additive properties.

Part of FoggedLens/deflock#145. Paired with the consumer PR: FoggedLens/deflockhopper_maps#14

Test plan

• node --test data/cameras/*.test.mjs tiles/cameras/*.test.mjs -- 109 tests pass, including atomic rejection of non-finite tokens and derived range overflow.
• shellcheck tiles/cameras/build.sh tiles/cameras/verify.sh tiles/cameras/verify-filter.sh.
• Main and filtered PMTiles built from the three-camera fixture and retained singular and aligned plural span properties at z12.
• Sabotage check: removing singular span publication caused three focused regressions; restoring it returned the focused suite to green.
• git diff --check.