a23ecaf4c1
Implements session-based analytics tracking that sends gameplay
stats to the Horchposten API. Adds stats.{c,h} for accumulating
per-session metrics (kills, deaths, shots, dashes, jumps, pickups,
damage, time) and analytics.{c,h} with EM_JS bridge for fetch()
calls to the backend. Client ID is persisted in localStorage.
Session start/end hooks are wired into all game lifecycle events
(level transitions, restart, quit, tab close via sendBeacon).
Analytics URL/key are configured via data attributes on the canvas
container. Non-WASM builds compile with no-op stubs.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>