docs: fix install section for Ubuntu/Debian and correct UI port

- Add venv guidance for Ubuntu 22.04+/Debian 12+ users who hit PEP 668
  error when running pip install system-wide (fixes conductor-oss/getting-started#34,
  conductor-oss/getting-started#35)
- Fix quickstart closing paragraph: localhost:8127 → localhost:8080
  (fixes conductor-oss/getting-started#40)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: nthmost-orkes

README.md

@@ -62,6 +62,14 @@ conductor server start
 pip install conductor-python
 ```
 
+> **Ubuntu / Debian users:** Python 3.12+ on Ubuntu 22.04+ and Debian 12+ blocks system-wide `pip install` by default ([PEP 668](https://peps.python.org/pep-0668/)). Use a virtual environment:
+>
+> ```shell
+> python3 -m venv conductor-env
+> source conductor-env/bin/activate
+> pip install conductor-python
+> ```
+
 ## 60-Second Quickstart
 
 **Step 1: Create a workflow**
@@ -162,7 +170,7 @@ python quickstart.py
 > See [Configuration](#configuration) for details.
 
 That's it — you just defined a worker, built a workflow, and executed it. Open the Conductor UI (default:
-[http://localhost:8127](http://localhost:8127)) to see the execution.
+[http://localhost:8080](http://localhost:8080)) to see the execution.
 
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