Add NWAC weather station data pages

[rchlfryn]

Description

Adds native weather-station data pages to AvyWeb for NWAC, recreating the nwac.us /weatherdata/<station>/now/ tables (currently a WordPress plugin). Data-first React tables backed by SnowObs, fetched server-side so the API token never reaches the browser.

Related Issues

N/A

Key Changes

• SnowObs service (src/services/snowobs): server-side wx/v1/station/data/timeseries fetch (token via SNOWOBS_TOKEN env), zod-validated response, and a pure transform → render-ready tables — cumulative precip, cross-station full-outer-join on timestamp, UTC→America/Vancouver, short sensor/unit labels. Unit-tested.
• Station registry (src/constants/weatherStations.ts): 32 station groups ported from the legacy station_group_tables_config — slug, legacySlug (for future redirects), region, stids, columns. Integrity-tested.
• Detail route /weather/stations/[station]: ISR (10-min revalidate), 24h / 7-day range toggle, latest-observation timestamp + stale flag (>2h), per-station error isolation, notFound() for centers without the stations platform.
• Index /weather/stations: region-grouped directory (up to 4 columns) + station picker.
• StationNowTable: shadcn table — zebra rows, sticky time column, tightened/centered columns, stacked label/unit/elevation headers.
• NWAC-only "Weather Data" nav item in the Weather dropdown (seed + provisioning + migration).

How to test

• pnpm dev, then load nwac.localhost:3000/weather/stations and /weather/stations/hurricane-ridge.
• Toggle Last 24 Hours / Last 7 Days; spot-check values against nwac.us.
• Confirm other centers (dvac/sac/snfac) 404 on these routes.
• pnpm test — covers the SnowObs transform and the registry.

Screenshots / Demo video

TODO: add a screenshot of the Hurricane Ridge table.

Migration Explanation

src/migrations/20260707_180000_add_nwac_weather_data_nav.ts adds the NWAC-only "Weather Data" built-in page (/weather/stations) and a Weather-dropdown nav item to the existing NWAC tenant. It is scoped to NWAC (no-op for other tenants), idempotent, and uses raw SQL for the nav update, mirroring the existing backfill_nav_builtin_pages migration.

Future enhancements / Questions

• SnowObs token: currently read from env with a public fallback token committed (the same one nwac.us already serves in client HTML). Consider dropping the fallback and requiring the env var to keep secret scanners happy.
• Region "area" pages with historical date-range browsing (prototyped separately, deferred).
• Data Portal graphs (legacy D3 → React charts).
• nwac.us cutover: redirects from /weatherdata/<slug>/now/ → new URLs (deferred; legacySlug is stored for this).

🤖 Generated with Claude Code

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[github-actions]

Migration Safety Check

Found 1 potential issue:

20260707_180000_add_nwac_weather_data_nav.ts

Warning (line 96): DELETE keyword detected - review for data loss

await db.run(sql`DELETE FROM _navigations_v WHERE parent_id = ${navId}`)

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Review these patterns and add backup/restore logic if needed. See docs/migration-safety.md for guidance.

[github-actions]

Preview deployment: https://featxweather-station-tables.preview.avy-fx.org