fix(pleno-vue): persist MiniMax API key across refresh + render fix (#281)

Fixes the operator-reported MiniMax configuration bug: the API key appeared to be 'not saved' on every refresh.

The api backend is correct — direct repro against api-v2.truckwash.io (2026-08-10 07:58) showed 200 on POST and `isSet: true` on subsequent GET for both `{variable, value}` and raw-key payload shapes. The bugs were all on the frontend.

## What was actually broken

1. **Read response shape mismatch (root cause).** `ConfigurationXLVask.refreshMiniMaxStatus` parsed the GET response as an object, but the endpoint returns `[{module, variable, type, value, isSecret, isSet}]`. `typeof array === 'string'` is false → `minimaxApiKeyIsSet` was reset to `false` after every reload.
2. **Inline edit-save flow never notified the parent.** `ConfigurationSecretKey` had no event out, so the inline edit-and-save on the api_key field always left `isSet=false` (and the warning visible) until the user fully reloaded the page.
3. **MiniMax 'Enable' toggle was bound to a function reference.** `:value="SessionUser.superUser.modules.minimax.config.enabled.get ? true : false"` evaluates as `function ? true : false` = `true` (every function is truthy), so the switch always rendered as on.
4. **Hardcoded English warning text** in `ConfigurationSecretKey.vue` — i18n-v2 violation.
5. **Missing key registration in `xlvask/Config.vue.keys`.** PR #269 added a switch for `minimax_integration_enabled` on `xlvask.config.keys`, but never registered the key — accessing `.set` on `undefined.set` throws `TypeError` and aborts the Vue render mid-tree. Production build #c353bfa only renders 3 of 4 categories because of this.

## Changes

- `ConfigurationSecretKey.vue` — emits `saved` after a successful `onSave`; stays in edit mode + surfaces error on failure. Warning title/body come from `useI18n` (`configuration.secret_key_not_set` + `common.warning`) with optional prop overrides.
- `ConfigurationXLVask.vue` — `extractConfigEntry` helper unwraps the array response and trusts the explicit `isSet` flag. The MiniMax enable toggle reads `minimaxEnabled` (real boolean) and re-fetches via `onMiniMaxEnabledSwitch` (optimistic rollback on failure). After re-authenticate/remove/inline-save the parent re-fetches status so the UI matches persistence.
- `xlvask/Config.vue.keys` — registers the missing `minimax_integration_enabled` key.
- New i18n key `configuration.secret_key_not_set` + global shared alias; added to da/de/en/no/sv.
- New `tests/unit/configuration-secret-key.spec.js` (4 tests).

## Verification (local)

- `npm run i18n:v2:check` ✅
- `npm run lint` ✅
- `npm run format:tests:check` ✅
- `npm run test:unit:fast` ✅ — 223 files / 1352 tests
- `npm run build` ✅

Companion api PR: #358 ("test(api): lock MiniMax config redaction + isSet contract") — already merged.

src/i18n/generated/en-v2.json

@@ -2372,6 +2372,7 @@
           "zip": "@:{'words.generated.zip'} @:{'words.generated.code'}"
         },
         "configuration": {
+          "secret_key_not_set": "The secret key is not set, please set it before enabling the integration.",
           "backups": {
             "active_jobs": "Active jobs",
             "actions": "Actions",