feat: add slave upgrade utility with dry-run default

README.md

@@ -4,16 +4,11 @@
 
 ## Install Master Layer
 
-From `jarvis-brain` repo root:
+From the standalone source repo:
 
 ```bash
-bash scripts/agent/bootstrap-mosaic.sh
-```
-
-Or directly from this package source:
-
-```bash
-bash userspace/mosaic/install.sh
+git clone https://git.mosaicstack.dev/mosaic/bootstrap.git ~/src/mosaic-bootstrap
+bash ~/src/mosaic-bootstrap/install.sh
 ```
 
 ## What It Provides
@@ -47,3 +42,17 @@ This creates/updates:
 - `.mosaic/` (repo-specific hook/config surface)
 - `scripts/agent/` (portable lifecycle scripts)
 - `AGENTS.md` (if missing)
+
+## Upgrade Existing Slave Repos
+
+Preview upgrades (dry-run):
+
+```bash
+~/.mosaic/bin/mosaic-upgrade-slaves
+```
+
+Apply upgrades:
+
+```bash
+~/.mosaic/bin/mosaic-upgrade-slaves --apply
+```