feature: mid-circuit measurement and feedforward support

[rmshaffer]

Issue #, if available:

Description of changes:
Follow-up of #293 to bring the changes into the main branch.

Testing done:

Merge Checklist

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General

• I have read the CONTRIBUTING doc
• I used the commit message format described in CONTRIBUTING
• I have updated any necessary documentation, including READMEs and API docs (if appropriate)

Tests

• I have added tests that prove my fix is effective or that my feature works (if appropriate)
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[codecov]

Codecov Report

❌ Patch coverage is 96.81866% with 30 lines in your changes missing coverage. Please review.
✅ Project coverage is 99.41%. Comparing base (d64f7bf) to head (6f1ec22).

Files with missing lines	Patch %	Lines
...default_simulator/openqasm/branched_interpreter.py	96.34%	2 Missing and 24 partials ⚠️
src/braket/default_simulator/branched_simulator.py	88.88%	4 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##              main     #306      +/-   ##
===========================================
- Coverage   100.00%   99.41%   -0.59%     
===========================================
  Files           48       51       +3     
  Lines         4156     5091     +935     
  Branches       432      674     +242     
===========================================
+ Hits          4156     5061     +905     
- Misses           0        6       +6     
- Partials         0       24      +24     

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