Fix DreamPipeline Golden Path Mermaid rendering

Part of #14310. Follow-up from the #14318/#14336 Dream Pipeline guide refresh.

Context

The operator reported on 2026-06-29 that learn/agentos/DreamPipeline.md now has a broken second Mermaid diagram: the Golden Path synthesis diagram no longer renders.

This is a regression in a public Agent OS guide and should be fixed separately from the currently claimed StrategicWorkflows.md dead-command lane (#14339), so the rendering defect is not hidden inside unrelated command de-staling work.

Live latest-open sweep: checked latest 20 open issues immediately before filing on 2026-06-29; no equivalent DreamPipeline Mermaid rendering bug found. A2A in-flight sweep: checked latest 30 messages; no competing lane-claim for this Mermaid render defect found.

The Problem

The guide is supposed to explain the REM loop and Golden Path with diagrams that render in GitHub/portal Markdown. After the Dream Pipeline rewrite, the second Mermaid block under ## Golden Path Synthesis no longer renders for the operator.

Broken surface:

• learn/agentos/DreamPipeline.md
• second Mermaid block, currently near the Golden Path synthesis section
• visible symptom: rendered guide loses the Golden Path synthesis diagram

The Architectural Reality

The guide is part of the #14310 documentation / learning-experience overhaul. It is not runtime code, but the diagram is still substrate: it teaches maintainers the shape of the Golden Path route surface.

Current source evidence before filing:

• learn/agentos/DreamPipeline.md contains two Mermaid blocks.
• The second one begins near line 201 with flowchart TD and defines the Golden Path synthesis graph.
• The diagram was changed by the #14318/#14336 guide refresh that is now on dev.

The Fix

Repair the second Mermaid block so it renders reliably in GitHub and the portal Markdown renderer while preserving the intended content:

• Recent session summaries
• Frontier baseline embedding
• Chroma graph query
• SQLite open-state / blocker / edge-weight checks
• Priority scoring
• sandman_handoff.md

Prefer a minimal syntax repair over rewriting the guide narrative. If the problem is a reserved identifier, punctuation incompatibility, or renderer-specific Mermaid syntax, rename/escape the diagram tokens rather than changing the conceptual model.

Acceptance Criteria

• The second Mermaid diagram in learn/agentos/DreamPipeline.md renders in the target Markdown surface.
• The diagram still communicates the Golden Path synthesis flow from summaries to sandman_handoff.md.
• No stale factual claims or dead commands are introduced while fixing the diagram.
• Validation evidence is captured in the PR body, including the exact render/parser check used.

Out of Scope

• Do not rewrite the Dream Pipeline narrative again.
• Do not change Golden Path runtime code.
• Do not fold in the cross-guide dead-reference sweep from #14327.
• Do not fold in StrategicWorkflows.md command de-staling from #14339.

Related

• Parent epic: #14310
• Source guide refresh: #14318 / PR #14336
• Active adjacent doc lane: #14339
• Later cross-guide reconciliation: #14327

Origin Session ID: f9ecf11e-78ce-4a48-b353-b970adf49d92

Retrieval Hint: DreamPipeline.md second Mermaid Golden Path synthesis diagram no longer renders after #14336