feat(server): serve the client-only build with Bun

Angular's server build needs Node loader hooks that Bun does not apply,
and every route is client-rendered, so Angular now builds a client-only
bundle and a small Bun.serve server delivers it: hashed assets with the
one-year cache, index.html revalidated, extension-less routes falling
back to index.html, missing assets 404, traversal and malformed paths
rejected, and other methods 405. Express, @angular/ssr and the unused
hydration provider are removed. Both Docker stages use the pinned
oven/bun:1.4.3-alpine image without Node, and the health checks use
Bun's fetch.

Refs #292

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

package.json

@@ -5,9 +5,10 @@
 		"ng": "ng",
 		"start": "bun scripts/generate-langs.js && ng serve",
 		"build": "bun scripts/generate-langs.js && ng build",
+		"postbuild": "bun build src/server.ts --target=bun --outfile dist/vac-optimizer/server/server.js",
 		"watch": "bun scripts/generate-langs.js && ng build --watch --configuration development",
 		"test": "bun scripts/generate-langs.js && bun test --isolate",
-		"serve:ssr:vac-optimizer": "bun dist/vac-optimizer/server/server.mjs",
+		"serve": "bun dist/vac-optimizer/server/server.js",
 		"lint": "bun scripts/generate-langs.js && eslint \"src/**/*.ts\"",
 		"lint:fix": "bun scripts/generate-langs.js && eslint \"src/**/*.ts\" --fix",
 		"format": "bun scripts/generate-langs.js && prettier --write \"src/**/*.{ts,html,scss,css,json}\"",
@@ -36,12 +37,9 @@
 		"@angular/material": "^22.0.0",
 		"@angular/platform-browser": "22.2.1",
 		"@angular/platform-browser-dynamic": "22.2.1",
-		"@angular/platform-server": "22.2.1",
 		"@angular/router": "22.2.1",
-		"@angular/ssr": "22.2.2",
 		"date-holidays": "^3.30.2",
 		"dayjs": "^1.11.21",
-		"express": "^5.2.1",
 		"rxjs": "~7.8.2",
 		"tslib": "^2.8.1"
 	},
@@ -52,7 +50,6 @@
 		"@angular/compiler-cli": "22.2.1",
 		"@eslint/js": "^10.0.1",
 		"@types/bun": "1.4.3",
-		"@types/express": "^5.0.6",
 		"@types/jsdom": "^21.1.7",
 		"@types/node": "^26.0.0",
 		"eslint": "^10.4.1",