Merge origin/main — unite all work onto one branch

Brings in dev log (NavLogger), UnitPrefs, MapLayerManager, HUD views,
conditions throttling, track save/load pipeline, improved ParticleWindView
(antimeridian-aware, dynamic particle count), Snackbar error surfacing,
and all other main-branch work from the prior session.

Combined with master's hardware source flags, vessel registry, crew
management, thermal alarm, CPA collision alerts, and track stats.

Also documents primary branch policy in CLAUDE.md and .agent/config.md:
all work merges to main, never master.

https://claude.ai/code/session_011h2dXbgXg3PesQMmQUNTCW

1 files changed, 56 insertions, 0 deletions

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+# Migrating from Navionics
+
+Welcome to Nav. This guide covers the key differences and how to move your data over.
+
+---
+
+## What's Different
+
+| Feature | Navionics | Nav |
+|---|---|---|
+| Charts | Navionics SonarChart + Raster | OpenFreeMap vector tiles |
+| Track recording | In-app GPX | GPX saved to Documents/Nav/ |
+| Trip log | Voyage log | Voice log (transcribed) |
+| Departure planning | None | Pre-trip briefing with sail plan |
+| Wind overlay | Basic | Wind particles + hourly forecast |
+
+---
+
+## Exporting Your Tracks from Navionics
+
+1. Open Navionics on your phone or tablet
+2. Go to **My Charts → Tracks**
+3. Tap a track → **Share → Export GPX**
+4. Save or AirDrop the `.gpx` file to your device
+
+---
+
+## Importing Tracks into Nav
+
+Nav automatically reads GPX files from the **Documents/Nav/** folder on your device.
+
+1. Move your exported `.gpx` files to `Documents/Nav/` using the Files app
+2. Re-open Nav — tracks are loaded on startup
+3. Similar-conditions trip comparison in the Pre-Trip Briefing will use these tracks
+
+---
+
+## Waypoints
+
+Nav does not currently manage waypoints. Use Navionics or a dedicated chart plotter for waypoint routing. Nav focuses on departure briefing, track recording, and the sail log.
+
+---
+
+## Charts
+
+Nav uses **OpenFreeMap** vector tiles. These are free, fast, and work well for coastal cruising. They do not include depth contours or hazard overlays — continue using Navionics or a NOAA chart app for navigation in unfamiliar waters.
+
+---
+
+## Daily Workflow
+
+**Before you sail:** Open the **Safety → Plan Trip** screen for your departure briefing — sail plan, heading recommendation, watch items, and a look at how conditions will change over your trip window.
+
+**On the water:** Tap **Log** to dictate voice notes. The GPS track records automatically when you tap the record button.
+
+**After you return:** The post-trip report summarises distance, duration, and max SOG.