Execution Log: Replace the README workflow mermaid diagram with an Excalidraw diagram

Append-only log of progress for the user's visibility. Checked in alongside the spec at docs/specs/issue-150/execution-log.md.

Tier 1–2 (trivial docs/diagram change, autonomy.tiers → autonomous-complete): the 3-phase spec is compact, locked on the operator's direct request, and iterated on the PR.

Phase transitions

Phase	Entered	Reviewed/approved by	Notes
implementation	2026-08-04		Direct user request; issue #150 filed, worked on claude/excalidraw-readme-workflow-uymiy4
needs-review	2026-08-04		PR opened; iterating with the user on the PR per their request
complete

Pull requests

PR	Scope / tasks	Status
#151	Excalidraw diagram + README embed	open

Progress entries

2026-08-04 — diagram authored, exported, embedded

• Phase: implementation → needs-review
• Did: Authored the workflow diagram as an Excalidraw scene (docs/assets/the-loop-workflow.excalidraw, generated programmatically so geometry stays consistent), exported it to docs/assets/the-loop-workflow.svg with Excalidraw's own exportToSvg (headless Chromium; Virgil font embedded as a data URI; exportEmbedScene on, so the SVG itself reopens in excalidraw.com), and replaced the README's mermaid flowchart TD with the SVG embed. Content is 1:1 with the mermaid original: ticket → (brainstorm) → requirements → design → tasks in the "specified and reviewed" zone, implement/self-check → self/critic review → evidence in the "executed autonomously" zone, then complete → learn, with the loop:<phase> labels as captions.
• Checkpoint/tests: pre-commit run markdownlint-cli2 --files README.md docs/specs/issue-150/execution-log.md green; SVG visually verified via headless Chromium screenshot.
• Next: iterate on the PR with the user.
• Blockers: none.

Review cycles

Cycle	Type (self/critic/security)	Reviewer	Outcome	Link
1	self (visual + content diff vs mermaid)	agent	new findings (label overflow, zone-title collision) — fixed	PR #151
2	self (re-render)	agent	zero (converged)	PR #151

Capability docs

No capability's current behaviour changes — the README's hero diagram is presentation, not a capability. No docs/capabilities/ doc references the mermaid block. Nothing to update.

Security review (gate)

• Mechanism: the-loop checklist
• Outcome: pass — static docs/image change; no code, config, or attack surface touched. The SVG is generated by Excalidraw's own exporter and contains no scripts.
• Human sign-off: n/a (tier below security.review.humanSignOffMinTier)

Final validation evidence

• README renders the new SVG in place of the mermaid block; the diagram carries the same nodes, edges, edge labels and phase labels as the mermaid original.
• docs/assets/the-loop-workflow.excalidraw is a valid scene (46 elements) and both it and the SVG round-trip through excalidraw.com.