feat: improve local dev with install path (#1221)

- also add better watcher support

<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit

- **New Features**
- Added a helper that displays a local installation URL to simplify
setting up the plugin.

- **Chores**
- Updated service and container port configurations to ensure consistent
network connectivity (changed from 8080 to 5858).
- Refined container management to gracefully handle running instances
during startup.
- Improved build and installation routines for streamlined deployment
and enhanced reliability.
- Enhanced documentation to clarify installation and usage instructions
for better user experience.
- Introduced a new document outlining development workflows for better
guidance.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

---
- To see the specific tasks where the Asana app for GitHub is being
used, see below:
  - https://app.asana.com/0/0/1209561202532053

plugin/scripts/entrypoint.sh

@@ -3,7 +3,7 @@
 mkdir -p /app/deploy/
 # Start http-server with common fileserver settings
 http-server /app/deploy/ \
-    --port 8080 \
+    --port 5858 \
     --host 0.0.0.0 \
     --cors \
     --gzip \