refactor: use PSR-18 discovery and replace auth token with headers

- Replaces hard Guzzle dependency with PSR-18 Client and PSR-17 Factory discovery.
- Refactors `Factory`and `Api` to use `ClientInterface` and `RequestFactoryInterface`.
- Replaces specific `authToken` handling with generic `headers` support in `Factory` and `Api`.
- Deprecates `Factory::withAuthToken()` in favor of `withHeader()`.
- Updates all embedding functions to use the discovered PSR-18 client.

BREAKING CHANGE: `Factory::withHttpClient` has been removed.

Author: CodeWithKyrian

chroma/chroma.sqlite3

@@ -16,13 +16,16 @@
   "license": "MIT",
   "require": {
     "php": "^8.1",
-    "guzzlehttp/guzzle": "^7.0"
+    "psr/http-client": "^1.0",
+    "psr/http-factory": "^1.1",
+    "php-http/discovery": "^1.20"
   },
   "require-dev": {
     "pestphp/pest": "^2.19",
     "symfony/var-dumper": "^6.3",
     "mockery/mockery": "^1.6",
-    "symfony/process": "^7.4"
+    "symfony/process": "^7.4",
+    "guzzlehttp/guzzle": "^7.10"
   },
   "autoload": {
     "psr-4": {
@@ -42,11 +45,12 @@
   ],
   "config": {
     "allow-plugins": {
-      "pestphp/pest-plugin": true
+      "pestphp/pest-plugin": true,
+      "php-http/discovery": true
     }
   },
   "scripts": {
     "test": "vendor/bin/pest",
     "test:coverage": "XDEBUG_MODE=coverage ./vendor/bin/pest --coverage"
   }
-}
+}