v0.40.0 — Cartographer

Every zone you cleared, drawn.

Added — 🗺 Cartographer (movement heatmap + route replay)

• 🗺 Movement heatmap. New Cartographer tab in Settings shows which parts of each zone you've walked, colored by density (log-normalized 64×64 grid, transparent→dark-blue→teal→yellow→warm-orange viridis ramp). The tool has been silently sampling your position at 1 Hz since v0.40 launched — run the same map twice and coverage builds up over time.
• ▶️ Route replay. Play / Pause / Jump-first / Jump-last controls plus a scrub slider let you replay your movement through any zone you've cleared. Watch where you backtracked, spot side rooms you missed. Speed presets: 1×, 4×, 16×, and Max (roughly 60 samples/sec at 60 FPS — 30 minutes of gameplay replays in ~30 seconds). Timestamp readout stays in sync with the scrub position.
• 🔐 Loopback-gated /api/tracks. Character-name query is served only to localhost — same privacy posture as v0.37 Codex. Position samples never leave your machine. /state continues to strip character identity.
• 🎯 Additive. No overlay changes; ignore the tab and nothing about your rig changes. Sample rate is a fixed 1 Hz on the render thread (30× downsampled from the world tick) — cheap enough to leave running forever.
• 💡 Discoverability card on the dashboard first-load flags the new feature for existing users. Dismissable with [×]; the dismissal persists via localStorage.

Under the hood

• New POE2Radar.Core.Tracks namespace: TrackSample record + TrackStore static class handles append/load/list against config/tracks/<sanitized-character>/<zone-code>.jsonl. Character-name + zone-code sanitize via the same letter/digit/underscore/hyphen rule as codex + palettes. 10K-sample ring cap with read-rewrite trim keeps the newest 9K on overflow. All exceptions swallowed on the render hot path.
• New TrackRecorder — 30-tick character-name stability gate (v0.37 pattern) + 1-Hz Stopwatch downsample gate + zone-change clock reset. Wired into RadarApp's per-tick observer next to SessionEventLog.
• New /api/tracks?character=<name>&zone=<code> (loopback-gated), /api/tracks/characters, /api/tracks/zones?character=<name> (both also loopback-gated). Non-GET methods return 405.
• New Cartographer dashboard IIFE: cascading character/zone selects → 64×64 density render → offscreen heatmap cache → route dotted-line overlay + gold marker at scrubbed sample index. requestAnimationFrame loop drives playback advance.

Tests

• 51 new xUnit facts across TrackStoreTests (16: append/roundtrip/sanitize/ring-cap/perf-under-cadence-budget), TrackRecorderTests (9: stability-gate/downsample/zone-change/silent-exception/happy-path), ApiTracksEndpointTests (13: 3 routes × gate/missing-param/happy/method), DashboardCartographerTabTests (6: HTML/JS/CSS structural), DashboardCartographerReplayTests (4: playback controls + speed presets + JS symbols), DashboardCartographerHintTests (3: hint card + dismiss). Full suite grows from 1061 to 1112 (all green).

Known limitations

• Per-session split — currently multiple runs of the same zone APPEND to the same track file (density accumulates). A "session filter" UI (view only the last N sessions) is v0.40.1 scope.
• Overlay heatmap layer — v1 is dashboard-only. A translucent grid drawn on the actual overlay is v0.41 scope.
• Export as PNG / GIF for streaming clip use — v0.40.1.
• Cross-zone aggregate ("all your Delirium mirror clears overlaid") — v0.40.1.

Upgrade

Fully additive — no config migration required. Position sampling starts writing the moment your character name stabilizes; if you don't want it, ignore the new dashboard tab. Existing installs upgrade cleanly.

Full Changelog: v0.39.1...v0.40.0