feat(ui): add a logger to change log level and permit better diagnostics

in this case logs are added in the delta upload worker

you can increase verbosity from console via:

```javascript
// Usage:
oxi.setLogLevel('oxi:upload', 'debug')    // deep dive
oxi.setLogLevel('oxi:upload', 'warn')     // quiet
oxi.log.setLevel('debug')                  // everything to debug
```

values are stored in localstorage

example:

```
oxi.setLogLevel('oxi:upload', 'debug');
'oxi:upload → debug'
deltaUpload.ts:120 [f32ce1] delta start {file: 'Revue de presseg.odp', size: 23658927}
deltaUpload.ts:185 [f32ce1] worker: worker start {file: 'Revue de presseg.odp', size: 23658927}
deltaUpload.ts:186 [f32ce1] worker: wasm loaded
deltaUpload.ts:186 [f32ce1] worker: hashed — blake3=150edbc35f3475a0bdeecd15fe5278dda305ce3b27e53e9c40515a69f0b883f3 (76 chunks)
deltaUpload.ts:186 [f32ce1] worker: negotiate: 76 hashes → 76 missing, 0 dedup'd
deltaUpload.ts:186 [f32ce1] worker: chunk PUT: 28 chunks, 8825338 bytes
deltaUpload.ts:186 [f32ce1] worker: chunk PUT: 29 chunks, 8950230 bytes
deltaUpload.ts:186 [f32ce1] worker: chunk PUT: 19 chunks, 5883663 bytes
deltaUpload.ts:186 [f32ce1] worker: ✅ committed — uploaded 23 658 927 B (no dedup, blake3=150edbc35f3475a0bdeecd15fe5278dda305ce3b27e53e9c40515a69f0b883f3)
deltaUpload.ts:185 [f32ce1] worker: commit HTTP 201 {blake3: '150edbc35f3475a0bdeecd15fe5278dda305ce3b27e53e9c40515a69f0b883f3', uploadedBytes: 23658927, reusedBytes: 0, totalBytes: 23658927, attempt: 0}
deltaUpload.ts:213 [f32ce1] delta done {file: 'Revue de presseg.odp', blake3: '150edbc35f3475a0bdeecd15fe5278dda305ce3b27e53e9c40515a69f0b883f3', savedBytes: 0, uploadedBytes: 23658927}
```

frontend/package-lock.json

@@ -8,7 +8,8 @@
       "name": "oxicloud-frontend",
       "version": "0.0.0",
       "dependencies": {
-        "@serenity-kit/opaque": "^1.1.0"
+        "@serenity-kit/opaque": "^1.1.0",
+        "loglevel": "^1.9.2"
       },
       "devDependencies": {
         "@eslint/js": "^10.0.1",
@@ -3969,6 +3970,19 @@
       "dev": true,
       "license": "MIT"
     },
+    "node_modules/loglevel": {
+      "version": "1.9.2",
+      "resolved": "https://registry.npmjs.org/loglevel/-/loglevel-1.9.2.tgz",
+      "integrity": "sha512-HgMmCqIJSAKqo68l0rS2AanEWfkxaZ5wNiEFb5ggm08lDs9Xl2KxBlX3PTcaD2chBM1gXAYf491/M2Rv8Jwayg==",
+      "license": "MIT",
+      "engines": {
+        "node": ">= 0.6.0"
+      },
+      "funding": {
+        "type": "tidelift",
+        "url": "https://tidelift.com/funding/github/npm/loglevel"
+      }
+    },
     "node_modules/lru-cache": {
       "version": "11.5.1",
       "resolved": "https://registry.npmjs.org/lru-cache/-/lru-cache-11.5.1.tgz",