feat(scripts): enhance find-unused.sh with deeper cross-referencing

scripts/find-unused.README.md

@@ -1,6 +1,6 @@
 # find-unused.sh
 
-Wrapper around [knip](https://knip.dev) that detects unused files and cross-references them against CI configs, package.json scripts, convention-based usage, and file-based routing directories to reduce false positives.
+Wrapper around [knip](https://knip.dev) that detects unused files and cross-references them against CI configs, build configs, package.json scripts, tsconfig files, convention-based usage, file-based routing directories, and sibling repo CI/CD pipelines to reduce false positives.
 
 ## Usage
 
@@ -10,17 +10,30 @@ bash scripts/find-unused.sh
 
 Requires `npx` (knip is fetched automatically). A fake `DATABASE_URL` is injected so config resolution doesn't fail.
 
+The script auto-detects whether it's running inside a factory layout (`../../.._repos/`). When inside a factory, it cross-references sibling repos. When standalone, it skips sibling checks gracefully and still runs all internal checks.
+
 ## What it does
 
 1. **Runs `knip --include files`** to get a list of unused files across the monorepo.
-2. **Cross-references** each file against:
-   - **CI / infra configs** — GitHub workflows, Dockerfiles, Vercel configs, Turbo config, Tauri config
-   - **package.json scripts** — all workspace `package.json` files
+2. **Indexes infra files** — collects all build/config/CI files into a single searchable set:
+   - GitHub workflow YAMLs
+   - Dockerfiles and docker-compose files
+   - Deployment configs (Vercel, Tauri)
+   - Build tool configs (vite, tailwind, postcss, next, drizzle, tsup, playwright)
+   - Build scripts (`.mjs`, `.ts`, `.sh` across all workspaces)
+   - `.opencode` skill scripts
+   - All `package.json` files (for script references)
+   - All `tsconfig*.json` files (for path aliases and includes)
+3. **Cross-references** each file against:
+   - **Internal infra** — all indexed config/build files, searching by filename and relative path
    - **Convention patterns** — filenames like `postinstall`, `drizzle.config`, Tauri hooks
-   - **File-based routing dirs** — Nuxt/Next server routes and API routes that are entry points by convention
-3. **Outputs a sorted list** (oldest first) with two categories:
-   - `✗` **Likely safe to remove** — no references found anywhere
-   - `⚠` **Review before removing** — referenced in CI, infra, convention, or routing
+   - **File-based routing dirs** — Next.js server routes, app routes, and API routes that are entry points by convention
+   - **Sibling repo CI/CD** — workflows, Dockerfiles, and build scripts in sibling repos and factory-level CI, with smart filtering to avoid false positives on generic filenames (e.g., `index`, `utils`, `config`)
+4. **Displays results in two buckets** (oldest first within each):
+   - `✗` **Safe to remove** — no references found anywhere (red)
+   - `⚠` **Review before removing** — referenced in infra/CI (yellow) or sibling CI (cyan)
+
+A progress indicator shows the current file being checked during cross-referencing.
 
 Certain paths are ignored entirely (scripts, dev tools) — see the `IGNORE_PREFIXES` array in the script.