Vite embedded build of Element Call (#3077)

* Embedded package build of Element Call

Part of https://github.com/element-hq/element-call/issues/2994

This creates a new "embedded" build (vs "full" build) at the vite level. It will be used by a later PR that actually provides platform specific packages.

Embedded build:

- Uses relative URLs
- Uses relative config.json path and other resource loading
- Has a config.json built in
- Doesn't include the public folder (e.g. favicon)

Out of scope:

- this doesn't attempt to exclude SPA functionality, so technically the build could be used in SPA
- the above means that the crypto-wasm binary is included in the build

* CI artifact name based on type of build

* Update src/config/Config.ts

package.json

@@ -3,8 +3,12 @@
   "version": "0.0.0",
   "type": "module",
   "scripts": {
-    "dev": "vite",
-    "build": "NODE_OPTIONS=--max-old-space-size=16384 vite build",
+    "dev": "yarn dev:full",
+    "dev:full": "vite",
+    "dev:embedded": "vite --config vite-embedded.config.js",
+    "build": "yarn build:full",
+    "build:full": "NODE_OPTIONS=--max-old-space-size=16384 vite build",
+    "build:embedded": "yarn build:full --config vite-embedded.config.js",
     "serve": "vite preview",
     "prettier:check": "prettier -c .",
     "prettier:format": "prettier -w .",
@@ -114,7 +118,8 @@
     "unique-names-generator": "^4.6.0",
     "vaul": "^1.0.0",
     "vite": "^6.0.0",
-    "vite-plugin-html-template": "^1.1.0",
+    "vite-plugin-generate-file": "^0.2.0",
+    "vite-plugin-html": "^3.2.2",
     "vite-plugin-svgr": "^4.0.0",
     "vitest": "^3.0.0",
     "vitest-axe": "^1.0.0-pre.3"