* fix(speed): fix speed counters showing 0 for custom subscription profiles
Fix an issue where proxy speed counters in the notification widget remain at 0 B/s for custom subscription profiles.
1. NotificationManager: Accumulate traffic stats for all non-direct and non-blocked outbound tags (stat.tag != TAG_BLOCKED) into proxy stats. Custom outbound tags in subscription JSONs (e.g., 'node-1', 'vless-hk', 'auto') are now correctly accounted for instead of being ignored.
2. CoreConfigManager: Ensure stats and policy (statsOutboundUplink / statsOutboundDownlink) sections are injected into custom JSON configurations when PREF_SPEED_ENABLED is enabled, and stripped when disabled.
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