move pi-mono into companion-cloud as apps/companion-os

- Copy all pi-mono source into apps/companion-os/
- Update Dockerfile to COPY pre-built binary instead of downloading from GitHub Releases
- Update deploy-staging.yml to build pi from source (bun compile) before Docker build
- Add apps/companion-os/** to path triggers
- No more cross-repo dispatch needed

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

packages/coding-agent/test/system-prompt.test.ts

@@ -0,0 +1,104 @@
+import { describe, expect, test } from "vitest";
+import { buildSystemPrompt } from "../src/core/system-prompt.js";
+
+describe("buildSystemPrompt", () => {
+  describe("empty tools", () => {
+    test("shows (none) for empty tools list", () => {
+      const prompt = buildSystemPrompt({
+        selectedTools: [],
+        contextFiles: [],
+        skills: [],
+      });
+
+      expect(prompt).toContain("Available tools:\n(none)");
+    });
+
+    test("shows file paths guideline even with no tools", () => {
+      const prompt = buildSystemPrompt({
+        selectedTools: [],
+        contextFiles: [],
+        skills: [],
+      });
+
+      expect(prompt).toContain("Show file paths clearly");
+    });
+  });
+
+  describe("default tools", () => {
+    test("includes all default tools", () => {
+      const prompt = buildSystemPrompt({
+        contextFiles: [],
+        skills: [],
+      });
+
+      expect(prompt).toContain("- read:");
+      expect(prompt).toContain("- bash:");
+      expect(prompt).toContain("- edit:");
+      expect(prompt).toContain("- write:");
+    });
+  });
+
+  describe("custom tool snippets", () => {
+    test("includes custom tools in available tools section", () => {
+      const prompt = buildSystemPrompt({
+        selectedTools: ["read", "dynamic_tool"],
+        toolSnippets: {
+          dynamic_tool: "Run dynamic test behavior",
+        },
+        contextFiles: [],
+        skills: [],
+      });
+
+      expect(prompt).toContain("- dynamic_tool: Run dynamic test behavior");
+    });
+  });
+
+  describe("prompt guidelines", () => {
+    test("appends promptGuidelines to default guidelines", () => {
+      const prompt = buildSystemPrompt({
+        selectedTools: ["read", "dynamic_tool"],
+        promptGuidelines: ["Use dynamic_tool for project summaries."],
+        contextFiles: [],
+        skills: [],
+      });
+
+      expect(prompt).toContain("- Use dynamic_tool for project summaries.");
+    });
+
+    test("deduplicates and trims promptGuidelines", () => {
+      const prompt = buildSystemPrompt({
+        selectedTools: ["read", "dynamic_tool"],
+        promptGuidelines: [
+          "Use dynamic_tool for summaries.",
+          "  Use dynamic_tool for summaries.  ",
+          "   ",
+        ],
+        contextFiles: [],
+        skills: [],
+      });
+
+      expect(prompt.match(/- Use dynamic_tool for summaries\./g)).toHaveLength(
+        1,
+      );
+    });
+  });
+
+  describe("SOUL.md context", () => {
+    test("adds persona guidance when SOUL.md is present", () => {
+      const prompt = buildSystemPrompt({
+        contextFiles: [
+          {
+            path: "/tmp/project/SOUL.md",
+            content: "# Soul\n\nBe sharp.",
+          },
+        ],
+        skills: [],
+      });
+
+      expect(prompt).toContain(
+        "If SOUL.md is present, embody its persona and tone.",
+      );
+      expect(prompt).toContain("## /tmp/project/SOUL.md");
+    });
+  });
+});