FN-7104: Align ce-brainstorm durable artifact references

Keep bundled ce-brainstorm guidance aligned with docs/plans as the durable planning artifact.

- Update the visual probe reference to name docs/plans as the durable artifact.
- Add a recursive skill-content guard that prevents docs/brainstorms from being described as new or durable output.
- Assert legacy docs/brainstorms wording remains limited to ce-plan inputs.

Files changed:
 .../__tests__/skill-content-alias-guard.test.ts    | 85 ++++++++++++++++++++++
 .../ce-brainstorm/references/visual-probes.md      |  2 +-
 2 files changed, 86 insertions(+), 1 deletion(-)

Fusion-Task-Id: FN-7104

Fusion-Task-Lineage: dd26a511-816d-479c-99ac-7cfec2b96bd4

Co-authored-by: Fusion (runfusion.ai) <noreply@runfusion.ai>

plugins/fusion-plugin-compound-engineering/src/__tests__/skill-content-alias-guard.test.ts

@@ -0,0 +1,85 @@
+import { readdirSync, readFileSync, statSync } from "node:fs";
+import { relative, join } from "node:path";
+import { fileURLToPath } from "node:url";
+import { describe, expect, it } from "vitest";
+
+const ceBrainstormRoot = fileURLToPath(new URL("../skills/ce-brainstorm/", import.meta.url));
+const visualProbesPath = join(ceBrainstormRoot, "references/visual-probes.md");
+const skillPath = join(ceBrainstormRoot, "SKILL.md");
+const brainstormSectionsPath = join(ceBrainstormRoot, "references/brainstorm-sections.md");
+
+function readUtf8(path: string): string {
+  return readFileSync(path, "utf8");
+}
+
+function listMarkdownFiles(root: string): string[] {
+  return readdirSync(root, { withFileTypes: true }).flatMap((entry) => {
+    const path = join(root, entry.name);
+    if (entry.isDirectory()) {
+      return listMarkdownFiles(path);
+    }
+    if (entry.isFile() && entry.name.endsWith(".md")) {
+      return [path];
+    }
+    return [];
+  });
+}
+
+function lineNumberForOffset(content: string, offset: number): number {
+  return content.slice(0, offset).split("\n").length;
+}
+
+/*
+FNXC:CompoundEngineering 2026-06-27-01:15:
+CE brainstorm and plan share a unified durable artifact under docs/plans/, while docs/brainstorms/ remains only a legacy input. This content guard protects the prompt-executed bundled skill text from regressing to a new-output or durable-artifact claim for docs/brainstorms/ during future upstream refreshes.
+*/
+describe("bundled ce-brainstorm docs/plans alias content", () => {
+  it("does not name docs/brainstorms as the durable or new brainstorm output", () => {
+    const forbiddenDurableOutputClaims = [
+      /docs\/brainstorms\/[^\n.]*\b(?:is|are)\b[^\n.]*\bdurable artifact\b/gi,
+      /(?:durable artifact|durable document|durable output|final requirements doc)[^\n.]*docs\/brainstorms\//gi,
+      /new\s+`?ce-brainstorm`?\s+outputs?\s+(?:write|go|land|belong)[^\n.]*docs\/brainstorms\//gi,
+    ];
+
+    const failures = listMarkdownFiles(ceBrainstormRoot).flatMap((path) => {
+      const content = readUtf8(path);
+      return forbiddenDurableOutputClaims.flatMap((pattern) => {
+        pattern.lastIndex = 0;
+        return Array.from(content.matchAll(pattern), (match) => {
+          const line = lineNumberForOffset(content, match.index ?? 0);
+          return `${relative(ceBrainstormRoot, path)}:${line}: ${match[0]}`;
+        });
+      });
+    });
+
+    expect(failures).toEqual([]);
+  });
+
+  it("keeps visual probes pointing at docs/plans for the durable artifact", () => {
+    const visualProbes = readUtf8(visualProbesPath);
+
+    expect(visualProbes).toContain(
+      "The requirements-only unified plan in `docs/plans/` is the durable artifact.",
+    );
+    expect(visualProbes).not.toContain(
+      "The final requirements doc in `docs/brainstorms/` is the durable artifact.",
+    );
+  });
+
+  it("keeps docs/brainstorms labeled as legacy input rather than new output", () => {
+    const skill = readUtf8(skillPath);
+    const brainstormSections = readUtf8(brainstormSectionsPath);
+
+    expect(skill).toContain(
+      "Historical `docs/brainstorms/*-requirements.{md,html}` files remain legacy inputs for `ce-plan`, but new `ce-brainstorm` outputs do not write there.",
+    );
+    expect(brainstormSections).toContain(
+      "Historical `docs/brainstorms/*-requirements.*` files remain valid legacy\ninputs. Do not migrate or rewrite them when creating new artifacts.",
+    );
+  });
+
+  it("keeps the ce-brainstorm skill directory present for recursive content checks", () => {
+    expect(statSync(ceBrainstormRoot).isDirectory()).toBe(true);
+    expect(listMarkdownFiles(ceBrainstormRoot).length).toBeGreaterThan(0);
+  });
+});

plugins/fusion-plugin-compound-engineering/src/skills/ce-brainstorm/references/visual-probes.md

@@ -125,4 +125,4 @@ Use OS temp by default because visual probes are disposable scratch:
     display-info.json
 ```
 
-Use `.context/compound-engineering/ce-brainstorm-visual/<run-id>/` only when the user explicitly wants to inspect, preserve, or curate the sketches after the session. The final requirements doc in `docs/brainstorms/` is the durable artifact.
+Use `.context/compound-engineering/ce-brainstorm-visual/<run-id>/` only when the user explicitly wants to inspect, preserve, or curate the sketches after the session. The requirements-only unified plan in `docs/plans/` is the durable artifact.