feat(TASK-12): beta telemetry — report endpoint + settings toggle

Backend: telemetry.report RPC builds anonymous health report with node ID
(SHA-256 hash of pubkey, truncated), version, uptime, container states,
CPU/RAM, federation peers, and recent alerts. Saves latest report to disk.
Requires analytics opt-in (existing analytics.enable/disable flow).

Frontend: "Beta Telemetry" section in Settings with enable/disable toggle.
Shows what data is and isn't collected. Mock backend handles all analytics
and telemetry RPCs.

Privacy: No wallet data, no private keys, no DIDs, no IP addresses.
Node identified by truncated hash only.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

core/archipelago/src/api/rpc/mod.rs

@@ -703,6 +703,7 @@ impl RpcHandler {
             "analytics.enable" => self.handle_analytics_enable().await,
             "analytics.disable" => self.handle_analytics_disable().await,
             "analytics.get-snapshot" => self.handle_analytics_get_snapshot().await,
+            "telemetry.report" => self.handle_telemetry_report().await,
 
             // Real-time metrics monitoring
             "monitoring.current" => self.handle_monitoring_current().await,