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/src/core/diagnostics.ts

@@ -0,0 +1,15 @@
+export interface ResourceCollision {
+  resourceType: "extension" | "skill" | "prompt" | "theme";
+  name: string; // skill name, command/tool/flag name, prompt name, theme name
+  winnerPath: string;
+  loserPath: string;
+  winnerSource?: string; // e.g., "npm:foo", "git:...", "local"
+  loserSource?: string;
+}
+
+export interface ResourceDiagnostic {
+  type: "warning" | "error" | "collision";
+  message: string;
+  path?: string;
+  collision?: ResourceCollision;
+}