Add speed test diagnostics to reports

[Sway-Chan]

What changed

• Add a recent speed-test diagnostics snapshot to SpeedTestService.
• Include the latest temporary speed-test sing-box config in exported diagnostic reports after existing redaction.
• Add per-node speed-test failure rows with serverId, node placeholder, outbound tag, and reason.
• Add endpoint-only resolved-IP probes for failed endpoint speed tests via DNS-over-TCP through that endpoint's HTTP inbound.
• Keep proxy-node target resolution marked as remote/opaque instead of inventing local resolved IPs.
• Include temporary speed-test core stdout/stderr in app.log at debug level, and let diagnostic capture raise the temporary core log level.

Why

When users report speed-test timeouts while nodes still work, the previous diagnostic report could show only aggregate failure reasons. It did not include the temporary speed-test config, per-node failures, or endpoint target DNS evidence, so endpoint geo-DNS issues still required guesswork.

Safety / privacy

• Temporary speed-test config goes through redactDeep before report rendering.
• Node identities still go through the existing collectNodeIdentifiers / redactIdentifiers pass.
• Custom speed-test target path/query is redacted in the report to avoid leaking endpoint tokens.
• Resolved-IP probing is only attempted for failed endpoint nodes; proxy nodes continue to rely on remote resolution and are not assigned fake local resolved IPs.

Validation

• npx jest src/shared/__tests__/diagnostic-redact.test.ts src/main/services/__tests__/speed-test-progress.test.ts src/main/services/__tests__/speed-test-endpoint-dns.test.ts src/main/services/__tests__/speed-test-warm-ttfb.test.ts src/main/services/__tests__/speed-test-coalesce.test.ts src/main/services/__tests__/speed-test-runner.test.ts src/main/services/__tests__/speed-test-concurrency.test.ts --runInBand
• npx tsc -p tsconfig.main.json --noEmit
• npx eslint src/main/services/SpeedTestService.ts src/main/services/DiagnosticService.ts src/main/index.ts src/shared/diagnostic-redact.ts src/shared/__tests__/diagnostic-redact.test.ts src/main/services/__tests__/speed-test-progress.test.ts src/main/services/__tests__/speed-test-endpoint-dns.test.ts

Review notes

An independent read-only agent review found issues around speed-test URL query redaction, endpoint DNS probe progress blocking, CONNECT non-200 socket cleanup, query construction errors, and stale docs wording. This branch addresses those findings before publication.