Replace 'gastown' with 'greenplace' in user-facing docs/examples

Using "greenplace" (The Green Place from Mad Max: Fury Road) as the
canonical example project/rig name in documentation and help text.
This provides a clearer distinction from the actual gastown repo name.

Changes:
- docs/*.md: Updated all example paths and commands
- internal/cmd/*.go: Updated help text examples
- internal/templates/: Updated example references
- Tests: Updated to use greenplace in example session names

Note: Import paths (github.com/steveyegge/gastown) and actual code
paths referencing the gastown repo structure are unchanged.

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

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

docs/operational-state.md

@@ -43,7 +43,7 @@ bd create --type=event --event-type=patrol.muted \
 
 # System entered degraded mode
 bd create --type=event --event-type=mode.degraded \
-  --actor=system:daemon --target=rig:gastown \
+  --actor=system:daemon --target=rig:greenplace \
   --payload='{"reason":"tmux unavailable"}'
 ```
 
@@ -230,10 +230,10 @@ Boot specifically:
 ```bash
 # System entered degraded mode
 bd create --type=event --event-type=mode.degraded \
-  --actor=system:daemon --target=rig:gastown \
+  --actor=system:daemon --target=rig:greenplace \
   --payload='{"reason":"tmux unavailable"}'
 
-bd update role-gastown --add-label=mode:degraded --remove-label=mode:normal
+bd update role-greenplace --add-label=mode:degraded --remove-label=mode:normal
 ```
 
 ## Configuration vs State