Auto-suggest intermediate waypoints from route templates (#234)

[msupino]

Summary
Suggest missing route waypoints from curated route templates instead of scanning every nearby nav waypoint.

Behavior

• Loads route templates in the background for map leg suggestions.
• Shows clickable waypoint chips on known template legs while Show nav waypoints is enabled.
• Clicking a chip inserts that named waypoint between the leg endpoints.
• Preserves manual leg speed, altitude, VOR reference, and blocked/one-way flags while resetting marker offsets.
• Keeps automatic leg-altitude lookup active when the original leg was auto-filled.

Tests

• Added route-template coverage for suggestion discovery, Show nav waypoints gating, chip click insertion, manual-field preservation, and automatic altitude refresh.
• Re-ran route editing coverage for existing single-click and double-click split behavior.

Fixes #234

[github-actions]

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https://msupino.github.io/NavigationApp/branch/auto-suggest-navwp/

Commit: 26697b1