feat: Add uniflight crate for duplicate request coalescing

[schgoo]

Adds uniflight, a crate for coalescing duplicate async tasks into a single execution. When multiple tasks request the same work (identified by a key), only the leader performs the work while followers wait and receive a clone of the result.

• Handles cancellation and panic gracefully (followers become the new leader)
• Includes comprehensive module documentation
• Includes example demonstrating cache thundering herd prevention

[schgoo]

@microsoft-github-policy-service agree company="Microsoft"

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 100.0%. Comparing base (0f5a87c) to head (61f8ce6).
⚠️ Report is 2 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #118   +/-   ##
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  Coverage   100.0%   100.0%           
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  Files         106      107    +1     
  Lines        6881     6980   +99     
=======================================
+ Hits         6881     6980   +99     

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[geeknoid]

I like the name :-)

[geeknoid]

The logo.png file isn't rendering for me. Is this a valid png file? I tried even going to your repo & branch, and GitHub won't show the image to me.

[schgoo]

@geeknoid I hadn't uploaded the logo yet. I just added it