Add resolver file import, CIDR parsing & stats

[AmirrezaFarnamTaheri]

• Add support for importing resolver files and gathering resolver statistics.
• Introduces a DB migration (v1->v2) adding resolverSourceType, resolverFileName, resolverCachedPath and resolverStatsJson to ProfileEntity.
• Adds ResolverAnalyzer utility to parse/analyze resolver text and cached files (CIDR expansion, stats serialization, import-to-cache).

UI updates:

• ProfilesScreen, Profile editor and SettingsScreen allow importing resolver files, show resolver stats, toggle CIDR parsing, and display scan ETA in HomeScreen/HomeStatusCards.
• VpnService now uses imported resolver files and logs stats; ConfigGenerator and client config gain RESOLVER_CIDR_ENABLED support.
• VpnManager tracks scan timestamps for ETA calculations.
• MTU logging was hardened to export each working resolver only once per session (new state in client, updated logic and unit test).
• Various strings/resources updated to support new UI flows.

[Hidden-Node]

Hi Amirreza, thanks for your contribution.

I've reviewed the changes, and while the DNS resolver and Android fixes are great, I noticed that some modifications were made to the client core files. Since this core is shared with another project, changing it here will cause major conflicts during future updates.

Please note that for this project, contributions should be limited to the android and mobile folders only. Please avoid making any changes outside of these directories to maintain core stability.

For this reason, I've decided to revert this PR for now. Could you please submit a new PR containing only the DNS and Android UI fixes, ensuring that the core directory remains untouched?

This way, I can safely merge your improvements without breaking core compatibility. Thanks for understanding and for your hard work!