refactor: move airports.json out of server/data into server/assets

server/data is for runtime state (SQLite, backups, logs, tmp) — the
airports snapshot is a shipped dataset, not user data, and it being in
there forced us to poke a hole in both .dockerignore and .gitignore.
Move it to server/assets/ and drop the exceptions; service and build
script point at the new path.

.dockerignore

@@ -3,7 +3,6 @@ client/node_modules
 server/node_modules
 client/dist
 data
-!server/data/airports.json
 uploads
 .git
 .github

.gitignore

@@ -17,7 +17,6 @@ client/public/icons/*.png
 
 # User data
 server/data/*
-!server/data/airports.json
 server/uploads/
 
 # Environment

server/scripts/build-airports.mjs

@@ -1,5 +1,5 @@
 #!/usr/bin/env node
-// Build server/data/airports.json from OurAirports (davidmegginson.github.io/ourairports-data).
+// Build server/assets/airports.json from OurAirports (davidmegginson.github.io/ourairports-data).
 // License: Public Domain. Keeps large/medium airports with an IATA code; timezone derived from coords via tz-lookup.
 
 import fs from 'node:fs'
@@ -9,7 +9,7 @@ import { fileURLToPath } from 'node:url'
 import tzLookup from 'tz-lookup'
 
 const __dirname = path.dirname(fileURLToPath(import.meta.url))
-const OUT = path.join(__dirname, '..', 'data', 'airports.json')
+const OUT = path.join(__dirname, '..', 'assets', 'airports.json')
 const SRC = 'https://davidmegginson.github.io/ourairports-data/airports.csv'
 
 function fetchText(url) {

server/src/services/airportService.ts

@@ -18,7 +18,7 @@ let byIata: Map<string, Airport> | null = null;
 
 function load(): Airport[] {
   if (cache) return cache;
-  const file = path.join(__dirname, '..', '..', 'data', 'airports.json');
+  const file = path.join(__dirname, '..', '..', 'assets', 'airports.json');
   if (!fs.existsSync(file)) {
     console.warn('[airports] airports.json missing — run `node scripts/build-airports.mjs`');
     cache = [];