Add support python 3.15

[p-r-a-v-i-n]

Description

Please explain the changes you are proposing.

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Related Issue(s)

Closes or relates to #

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Checklist

• I have referenced relevant issue numbers above
• I have performed a self-review of my code and it follows
  the style guidelines of this project
• I have added new or used existing tests that prove my fix
  is effective or that my feature works
• I have added necessary documentation (if appropriate) and
  updated the changelog
• I have added an AI assistance disclosure file (required!)
  in this PR

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AI Assistance Disclosure File

⚠️ Required for this PR: You MUST include a disclosure
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disclosure file must follow the exact format and content as
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Example 1 file contents of your disclosure file
.audit/<branch-name>.md:

## AI Assistance Disclosure

- [ ] I did **not** use any AI-assistance tools to help create this pull request.
- [x] I **did** use AI-assistance tools to *help* create this pull request.
- [x] I have read, understood and followed the projects' [AI Policy](https://github.com/crossbario/autobahn-python/blob/main/AI_POLICY.md) when creating code, documentation etc. for this pull request.

Submitted by: @your-github-username
Date: 2026-09-27
Related issue(s): #issue-number
Branch: python315

OR

Example 2 file contents of your disclosure file
.audit/<branch-name>.md:

## AI Assistance Disclosure

- [x] I did **not** use any AI-assistance tools to help create this pull request.
- [ ] I **did** use AI-assistance tools to *help* create this pull request.
- [x] I have read, understood and followed the projects' [AI Policy](https://github.com/crossbario/autobahn-python/blob/main/AI_POLICY.md) when creating code, documentation etc. for this pull request.

Submitted by: @your-github-username
Date: YYYY-MM-DD
Related issue(s): #issue-number
Branch: branch-name

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Submitting code generated primarily by AI, or for which you
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Example 1 OR Example 2 show the only valid two variants. You
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must always have the last tick checked.

Well, "must" if you want your PR to be accepted and ultimately
merged that is. Of course you are always free to
Go ahead! Fork my Day. (TM) ;) This is Open-source.