Add self-modifying harness docs and edge-case benchmark

[MagMueller]

Summary

• Add a self-modifying harness docs page that explains the inspect, patch, retry, verify loop
• Cover four concrete edge cases: canvas signature, file upload, drag and drop, and coordinate-only targets
• Add a standalone docs/edge-case-benchmark.html page that exercises those four mechanics and exposes window.edgeBenchmark.results
• Link the new docs from the README

Validation

• python3 HTML parser accepted docs/edge-case-benchmark.html
• Ran the benchmark through Browser Harness remote browser: signature=true, upload=true, drag=true, coordinate=true
• Saved verification screenshot at /tmp/browser-harness-edge-benchmark-result.png
• env -u BU_CDP_URL -u BU_CDP_WS uv run --with pytest pytest -q tests/unit -> 77 passed

Pass/fix notes from benchmark run

• Canvas signature passed with a CDP pointer stroke after reading the canvas geometry
• File upload passed with upload_file() plus explicit input/change events
• Drag/drop passed with a task-specific DataTransfer helper
• Coordinate target passed with geometry-derived click_at_xy()
• Initial data-URL navigation was flaky in the installed harness, so the run injected the benchmark HTML into about:blank via document.write()

---

Summary by cubic

Adds a self-modifying harness guide and a standalone browser benchmark to validate canvas signatures, uploads, drag-and-drop, and coordinate-only targets. The benchmark exposes window.edgeBenchmark.results for quick automated checks.

• New Features
  • New docs/self-modifying-harness.md: explains the inspect → patch → retry → verify loop with four edge-case walkthroughs.
  • Added docs/edge-case-benchmark.html: exercises the four mechanics and exposes window.edgeBenchmark.results for verification.
  • Updated README.md to link the new docs and benchmark.

^{Written for commit a9a6977. Summary will update on new commits.}

[cubic-dev-ai]

1 issue found across 3 files

Prompt for AI agents (unresolved issues)

Check if these issues are valid — if so, understand the root cause of each and fix them. If appropriate, use sub-agents to investigate and fix each issue separately.


<file name="docs/edge-case-benchmark.html">

<violation number="1" location="docs/edge-case-benchmark.html:323">
P2: The coordinate task can be passed via synthetic/programmatic click events, so it does not reliably enforce a real coordinate-driven pointer action.</violation>
</file>

_{Reply with feedback, questions, or to request a fix. Tag @cubic-dev-ai to re-run a review, or fix all with cubic.}

[cubic-dev-ai]

P2: The coordinate task can be passed via synthetic/programmatic click events, so it does not reliably enforce a real coordinate-driven pointer action.

Prompt for AI agents

Check if this issue is valid — if so, understand the root cause and fix it. At docs/edge-case-benchmark.html, line 323:

<comment>The coordinate task can be passed via synthetic/programmatic click events, so it does not reliably enforce a real coordinate-driven pointer action.</comment>

<file context>
@@ -0,0 +1,328 @@
+      }
+    });
+
+    document.getElementById("coordinate-target").addEventListener("click", () => {
+      setPass("coordinate", "red target clicked");
+    });
</file context>