feat(desktop): export main process telemetry over OTLP

[yordis]

What Changed

The Electron main process now exports logs and metrics alongside the traces it
already exported, and resolves all three endpoints from the same two sources the
backend uses: T3CODE_OTLP_TRACES_URL / _METRICS_URL / _LOGS_URL, then the
observability block in the server settings file. It reports as service
desktop, so a collector shows it beside the backend rather than mixed into it.

Where an OTLP logs endpoint is configured, the main process swaps
Logger.tracerLogger for the OTLP logger, matching what the server does in
#12493: both reach a collector, but the tracer logger covers only messages
logged inside a recorded span and files them under traces, while log records
carry every message stamped with its trace and span ids. Keeping both would
export each in-span message twice. With no logs endpoint configured, nothing
changes and messages keep landing in desktop.trace.ndjson as span events.

Logs, traces, and metrics are assembled in one place because Logger.layer
writes the whole logger set rather than adding to it, so a future refactor that
splits the OTLP logger back into a layer of its own silently drops either it or
the console output. There is a comment on the assembly saying so.

Why

The main process owns app startup, window and menu handling, backend
supervision, and updates. None of that is visible to the backend it launches, so
an operator who has wired up a collector still has a blind spot over the shell
around the server, and the desktop app is the surface most users install first.

Settings is read once for all three signals rather than per signal, so the main
process cannot resolve traces against one revision of the file and logs against
another.

Checklist

• This PR is small and focused
• I explained what changed and why
• I included before/after screenshots for any UI changes
• I included a video for animation/interaction changes

Summary by CodeRabbit

• New Features

  • Added desktop observability export for logs, metrics, and traces through configurable OTLP endpoints.
  • Endpoints can be configured through environment variables or application settings, with environment values taking precedence.
  • Desktop activity—including startup, window handling, updates, and backend supervision—is reported separately.

• Documentation

  • Updated observability documentation to describe desktop telemetry coverage and configuration.

[macroscopeapp]

Approvability

Verdict: Not approved

Macroscope's review found this PR not approvable — This PR adds a cross-cutting desktop main-process telemetry capability covering OTLP logs, metrics, and traces, including a changed log-export path when configured. Although network export remains opt-in and is tested, the exporter lifecycle and runtime behavior merit human review.

^{You can add or adjust custom eligibility rules. Learn more.}

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

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Review profile: CHILL

Plan: Advanced

Run ID: 9a15013a-4040-4dc5-a05f-2519b91b41fe

📥 Commits

Reviewing files that changed from the base of the PR and between c1b141c and 96d3c30.

📒 Files selected for processing (1)

• apps/desktop/src/app/DesktopObservability.test.ts

🚧 Files skipped from review as they are similar to previous changes (1)

• apps/desktop/src/app/DesktopObservability.test.ts

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📝 Walkthrough

Walkthrough

The desktop observability layer now resolves trace, metric, and log endpoints from environment variables or Settings. It conditionally configures OTLP exporters and adds tests and documentation for desktop telemetry wiring.

Changes

Desktop observability exports

Layer / File(s)	Summary
Endpoint resolution and Settings loading apps/desktop/src/app/DesktopObservability.ts, apps/desktop/src/app/DesktopObservability.test.ts	The desktop process reads trace, metric, and log endpoints. Environment values override persisted Settings values. Tests cover Settings fallback and endpoint configuration.
Telemetry layer and export wiring apps/desktop/src/app/DesktopObservability.ts, apps/desktop/src/app/DesktopObservability.test.ts, docs/operations/observability.md	The telemetry layer conditionally adds OTLP logging, metrics, and tracing. Tests cover log and metric export and disabled export. Documentation describes desktop runtime wiring and service naming.

Priority: ⬇️ Low

Estimated code review effort: 3 (Moderate) | ~25 minutes

Change: Feature

Sequence Diagram(s)

sequenceDiagram
  participant DesktopProcess
  participant telemetryLayer
  participant OtlpExporter
  participant OtlpEndpoint
  DesktopProcess->>telemetryLayer: Initialize observability
  telemetryLayer->>OtlpExporter: Configure enabled telemetry exporters
  OtlpExporter->>OtlpEndpoint: Export logs, metrics, or traces

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🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly and concisely describes the main change: exporting desktop main-process telemetry over OTLP.
Description check	✅ Passed	The description includes the required What Changed, Why, and Checklist sections. It explains endpoint resolution, logging behavior, service naming, and the reason for the change. No UI changes are des…
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check. Docstring coverage is scoped to functions touched by this diff. Analyzed 0 functions across 2…
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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