depr: tn1 retirement

[rmshaffer]

Issue #, if available:

Description of changes:
TN1 will be retired on 2026-06-26. Preparing the corresponding SDK changes here.

Testing done:

Merge Checklist

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 100.00%. Comparing base (a9cc73a) to head (1fd5cf6).

Additional details and impacted files

@@            Coverage Diff            @@
##              main     #1307   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files          171       171           
  Lines        11403     11401    -2     
  Branches      1481      1480    -1     
=========================================
- Hits         11403     11401    -2     

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[laurencap]

Why private rather than removed?

[rmshaffer]

This is currently the pattern for all retired devices in this file. The idea is that this would prevent retired devices from showing up in API docs or IDE autocomplete, but still keep a visible record in case users were relying on it. Open to other suggestions though; probably we shouldn't just accumulate these forever.

[virajvchaudhari]

Before we merge this we would also have to account for example notebooks or any other tests using this.

[rmshaffer]

Before we merge this we would also have to account for example notebooks or any other tests using this.

The example notebooks have been updated and merged, see: amazon-braket/amazon-braket-examples#933