fix: hysteria2 obfs round-trip, subscription identity, log scroll anchoring

[PhoenixNil]

Summary

A bundle of independent fixes/improvements on net10.

Hysteria2 salamander obfs round-trip (NodeLinkParser, NodeLinkSerializer)

obfs=salamander + obfs-password from share links is now merged into the Finalmask JSON's udp[] array, and re-emitted back out when generating share links. Previously these parameters were dropped on import and never produced on export.

Subscription refresh identity key (ServerListViewModel)

Node Id preservation across subscription refresh now keys on a multi-field tuple — protocol, host, port, network, security, path, credentials, uuid, flow, encryption, public key, short id — instead of just protocol://host:port. Case-insensitive fields are lowercased; credentials/keys are only trimmed. Queue-based matching handles duplicates correctly, and a reusedIds set prevents the same old Id from being assigned to multiple new entries.

Log window scroll anchoring (LogWindow.xaml.cs)

When auto-scroll is OFF and the 500-line ring buffer evicts old lines, the visible region used to drift upward. Now tracks linesReceived vs net buffer growth, computes the evicted count, and shifts the scroll offset down by evicted × lineHeight so visible content stays anchored.

Finalmask textbox truncation (DialogService)

AcceptsReturn = true must be set before Text — the single-line Text setter truncates at the first \r. Object initializers assign in declared order, so the property order in the initializer block matters. Reordered and normalized line endings to \r.

Shadow re-wiring guard (ServerDetailControl.xaml.cs)

Three AI-service Borders share ShadowRect_Loaded. Without a guard, each Loaded firing re-added all three AIShadowCastGrid receivers, ending at 9 entries with duplicates causing wasted compositor work. Added _shadowsWired bool.

x:Bind cleanup (MainWindow.xaml)

Child VM bindings (ServerList, ServerDetail, ControlPanel) and SwitchToSelectedServerCommand are immutable after MainViewModel construction, so they're now OneTime instead of OneWay. Also drops a redundant Mode=OneWay on the MiniStartStopCommand Command binding.

Test plan

• Hysteria2: import a share link with obfs=salamander&obfs-password=xxx, verify the salamander entry appears under Finalmask.udp[] and the regenerated share link contains both params.
• Subscription: refresh a subscription where two nodes share host:port but differ by uuid/network — both should keep their Ids.
• Log window: turn off auto-scroll, scroll up to mid-buffer, generate >500 log lines, confirm the visible region stays anchored.
• Finalmask dialog: edit a Hysteria2 server's Finalmask containing multi-line JSON, confirm full content shows in the TextBox.
• ServerDetail: inspect the AI-service cards on first show — no visual artifacts, shadow count stable.