perf(selfhost): profile stack resources and tune defaults

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Parent: #1819

Context

The self-host stack includes the app, Redis, optional Qdrant, optional Ollama, observability services, Grafana, Loki, Tempo, runners, backup services, and optional reverse-proxy/tailnet pieces. The default stack should be practical for maintainers without wasting resources or hiding heavyweight tradeoffs.

This issue profiles the stack and tunes defaults before official release.

Requirements

• Measure CPU, memory, disk, image size, startup time, and steady-state behavior across minimal, observability, qdrant, ollama, runners, and backup profiles.
• Identify services that should remain opt-in, services that need resource limits, and defaults that should change before release.
• Review Redis maxmemory policy, Prometheus/Loki/Tempo retention, Grafana plugin install overhead, Qdrant/Ollama startup expectations, and queue concurrency defaults.
• Audit image size and bundled tools; decide whether a smaller image variant is needed.
• Keep beginner-friendly defaults without pretending heavy profiles are free.
• Document expected resource envelopes and warning signs.

Deliverables

• Resource profile matrix for common deployment modes.
• Recommended compose defaults and optional resource limits.
• Image-size audit and optimization recommendations.
• Dashboard or docs updates showing how to inspect resource pressure.
• Follow-up PRs for any safe tuning changes.

Acceptance criteria

• Operators can choose profiles with realistic CPU/memory/disk expectations.
• Minimal self-host installs do not pull or run heavyweight optional services.
• Observability retention and runner profiles are documented with operational costs.
• Any resource limit or default change preserves reliability under normal review load.

Validation

• Capture representative docker stats / image-size / disk-use snapshots from a non-sensitive environment.
• Run readiness and focused self-host smoke checks after tuning changes.
• Confirm docs build and relevant tests pass.

Ownership

Maintainer-only. No gittensor:* labels.