feat(06-01): typed-array A* + turn classifier + step derivation + public exports (GREEN)
- routeAstar: allocation-free hot loop — binary heap of node indices over
preallocated typed arrays (grown by doubling), typed-array g/closed/
came-from, on-demand cached haversine/maxSpeed heuristic (admissible +
consistent); oneway-reverse edges never relaxed; unreachable -> null
- A1 proves A* == brute-force Dijkstra on ALL 625 mini-graph pairs
- classifyTurn: the one turn authority (compass convention — negative
delta = left; plan's (0,40)->slight-left case contradicted its own
(0,-90)/(0,90) pins, documented deviation); TURN_* constants exported
for plan 07's cron projection
- deriveSteps: splits at non-straight bearings or name changes; steps
carry kind/name/distanceM + polyline6; depart-first, arrive-last
- index.ts: engine-A named exports + ladder note updated — backend #2 is
now 'engine-a' (D-01 supersedes the wasm-router note; Valhalla port
infeasible + geojson-path-finder rejected, engine B = post-v1
evolution, D-02); createHttpRoutingSource deliberately absent (plan 04)
araharah-executor
e34c2296f5