[codex] Stage Python SDK beta versions from release tags (#24872)

## Summary
- Treat `sdk/python` as a development template with source version
`0.0.0-dev`, matching the existing Python runtime packaging pattern.
- Have `python-v*` tags supply the published SDK beta version through
the existing `stage-sdk --sdk-version` path.
- Remove the workflow check requiring a source version bump for each
beta release and remove its now-unused host Python setup step.
- Keep the reviewed runtime dependency pin at
`openai-codex-cli-bin==0.132.0`.
- Remove beta-number-specific documentation so it does not need editing
for each publish.

## Why
The package staging script already writes the release version into the
artifact. Requiring the checked-in SDK template version to match every
tag adds release-only source churn without changing the package users
receive.

## Validation
- Not run locally; relying on online CI for this workflow and metadata
change.

## Release
After this PR lands, publish the next beta by pushing tag
`python-v0.1.0b2` from merged `main`.

sdk/python/docs/faq.md

@@ -10,8 +10,7 @@ After a stable release exists, pass `--pre` to opt into newer prereleases.
 ## Why does the SDK install a runtime package?
 
 The SDK and runtime packages are versioned independently. Each SDK release
-pins one compatible runtime dependency, so `openai-codex==0.1.0b1` installs
-`openai-codex-cli-bin==0.132.0` automatically.
+pins and installs one compatible runtime dependency automatically.
 
 ## Thread vs turn
 

sdk/python/docs/getting-started.md

@@ -11,12 +11,6 @@ Install the SDK:
 pip install openai-codex
 ```
 
-For a reproducible install of this release:
-
-```bash
-pip install openai-codex==0.1.0b1
-```
-
 Requirements:
 
 - Python `>=3.10`