[Task][RFC]: Qualify DSH/Pi observation and managed-runtime selection

[huangruiteng]

Outcome / 目标

验收 DSH/Pi 观测与托管运行时选择。One task tracks this RFC's delivery; keep implementation PRs and milestone evidence here instead of creating a parallel task tree.

Canonical design: RFC. Roadmap: S4/S10/S11, under #4574. Design acceptance is distinct from implementation, live qualification and promotion.

Current boundary

Source audit: main at ce3862e33 (2026-09-28). This is source/PR inspection, not a new test or live-qualification claim.

DSH is the first L1 event source, not an automatically preferred production runtime. Combined diagnostic status/receipt readback exists; mode/session support and manager transport have separate partial evidence.

Work remaining

• Complete the RFC’s C0/C1, overhead and retention/deletion decision record before claiming an observer-qualified profile.
• Separately qualify managed lifecycle behavior and make runtime selection follow explicit user intent and current readiness; retain Pi as a candidate, not a predetermined migration.

Ownership and ongoing work

This task owns comparative runtime/observer evidence. Session-mode RFC owns admission, and reliability-diagnostics RFC owns diagnostic product/retention. Reuse existing providers and #3243; no live model spend or retention deletion is granted by issue publication.

Contribution route: implementation/integration overlaps active work. Start from the linked current owners/PRs and identify an unowned acceptance gap in a claim comment; do not begin a competing rewrite.

Acceptance

• Freeze treatments and thresholds before authorized experiments; preserve failed runs, uncertainty and no-uplift outcomes.
• Exact session/run identity and observation age prevent a stale goal ledger being shown as current health.
• Start/resume/interrupt/close, crash and duplicate completion preserve one executor; observation cannot influence prompts or scheduler decisions.
• Reconcile the RFC's current delivery checkpoint and this issue with the integrated revision, commands, passed/failed/untested evidence and remaining gates. Close the accepted scope only; no claim that a merged PR alone completes the RFC.

Starting points and delivery boundary

• packages/dsh-loopx-plugin
• loopx/capabilities/reliability_diagnostics
• loopx/control_plane/turn_driver

Base: latest main. Reuse the existing typed owner and provider boundaries. Include affected CLI/frontend/Lark companions; verify real entrypoints and backend where changed. Preserve existing first-screen review and maintainer merge gates. Public artifacts contain only synthetic/public-safe evidence, no private operational state. This task does not authorize provider promotion, benchmark launches, release/deployment or unrelated protected effects.