Merge remote-tracking branch 'origin/master' into gitea/feature/end

Resolved conflicts taking origin/master (v0.5.55) as canonical, with local
features re-applied:
- runtime log level (LOG_LEVEL env + dashboard Settings → Logging, applied
  immediately and persisted across restarts)
- free/noAuth provider enable/disable toggle via providerStrategies.enabled
- parallel model testing (Test All Models / Test Selected Keys)

tests/README.md

@@ -4,25 +4,26 @@ Unit tests for the `/v1/embeddings` endpoint implementation.
 
 ## Setup
 
-Vitest must be installed globally or in `/tmp/node_modules` (due to npm workspace hoisting from the root Next.js project):
+Install test dependencies from the `tests/` directory:
 
 ```bash
-cd /tmp && npm install vitest
+cd tests/ && npm install
 ```
 
 ## Running Tests
 
-```bash
-cd tests/
-NODE_PATH=/tmp/node_modules /tmp/node_modules/.bin/vitest run --reporter=verbose --config ./vitest.config.js
-```
-
-Or using the package script (from the `tests/` directory):
+From the `tests/` directory:
 
 ```bash
 npm test
 ```
 
+Or run vitest directly with npx:
+
+```bash
+npx vitest run --reporter=verbose --config ./vitest.config.js
+```
+
 ## Test Files
 
 | File | What it tests |