docs: fix README and PLUGIN.md documentation issues

- Clarify that `bd ready` shows issues ready to work on (#512)
- Update git hooks install command from deprecated script to `bd hooks install` (#513)
- Fix Claude Code plugin local install: use `./beads` not `.`, clarify shell vs CC commands (#514)

Fixes #512, #513, #514

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

docs/PLUGIN.md

@@ -40,17 +40,22 @@ There are two ways to install the beads plugin:
 #### Option 2: Local Development
 
 ```bash
-# Clone the repository
+# Clone the repository (shell command)
 git clone https://github.com/steveyegge/beads
 cd beads
+```
 
-# Add local marketplace
-/plugin marketplace add .
+Then in Claude Code:
+```
+# Add local marketplace (Claude Code command - note: use ./beads not .)
+/plugin marketplace add ./beads
 
 # Install plugin
 /plugin install beads
 ```
 
+**Note:** If you want to install the plugin from a different repo, first `cd` to that repo's directory in your terminal, then use `./beads` (or the relative path to the beads directory) in Claude Code.
+
 ### Restart Claude Code
 
 After installation, restart Claude Code to activate the MCP server.