fix: extract hardcoded English strings to i18n system with Russian translations

- Extract ~40 hardcoded strings from project detail, deploy, settings, credentials, registries, auth, env editor pages
- Add corresponding Russian translations
- Replace native confirm() default labels with i18n keys in ConfirmDialog
- Fix InstanceCard pluralization to use i18n

web/src/routes/settings/+page.svelte

@@ -290,7 +290,7 @@
 				<FormField label={$t('settingsGeneral.dockerNetwork')} name="network" bind:value={network} placeholder="staging-net" helpText={$t('settingsGeneral.dockerNetworkHelp')} />
 				<FormField label={$t('settingsGeneral.subdomainPattern')} name="subdomainPattern" bind:value={subdomainPattern} placeholder="stage-{'{stage}'}-{'{project}'}" helpText={$t('settingsGeneral.subdomainPatternHelp')} />
 				<FormField label={$t('settingsGeneral.pollingInterval')} name="pollingInterval" type="number" bind:value={pollingInterval} placeholder="60" error={errors.pollingInterval ?? ''} helpText={$t('settingsGeneral.pollingIntervalHelp')} />
-				<FormField label="Base Volume Path" name="baseVolumePath" bind:value={baseVolumePath} placeholder="/data" helpText="Prepended to relative volume sources (e.g., /data + my-app/uploads = /data/my-app/uploads)" />
+				<FormField label={$t('settingsGeneral.baseVolumePath')} name="baseVolumePath" bind:value={baseVolumePath} placeholder="/data" helpText={$t('settingsGeneral.baseVolumePathHelp')} />
 				<FormField label={$t('settingsGeneral.notificationUrl')} name="notificationUrl" bind:value={notificationUrl} placeholder="https://notify.example.com/webhook" error={errors.notificationUrl ?? ''} helpText={$t('settingsGeneral.notificationUrlHelp')} />
 			</div>
 			<!-- SSL Certificate -->