docs: add pip install path to installation, quickstart, updating, and CLI reference

Document pip install hermes-agent as a first-class install option.
Clarify that PyPI releases track tagged versions (major/minor),
not every commit on main — git installer is for bleeding-edge.

website/docs/getting-started/quickstart.md

@@ -48,7 +48,15 @@ Pick the row that matches your goal:
 
 ## 1. Install Hermes Agent
 
-Run the one-line installer:
+**Option A — pip (simplest):**
+
+```bash
+pip install hermes-agent
+```
+
+PyPI releases track tagged versions (major/minor releases), not every commit on `main`. For bleeding-edge, use Option B.
+
+**Option B — git installer (tracks main branch):**
 
 ```bash
 # Linux / macOS / WSL2 / Android (Termux)