doc: add usecases of labgrid

[ozan956]

Description

This PR adds a new documentation page describing common labgrid use cases across different deployment sizes and ownership models.

The document tries to make the following more explicit:

• where the current labgrid model feels natural and effective
• where operational friction becomes more visible, especially in larger shared labs
• why these differences matter when discussing future usability improvements

The goal is to document the different environments in which labgrid is used and to give more structure to discussions around usability for shared lab setups.

Related to:

• Challenges and Improvements for Large-Scale Labgrid Deployments and Client Usability #1861

Checklist

• Documentation for the feature

[ozan956]

cc @pamolloy @gastmaier @dlech @threexc @khilman @sjg20

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 46.0%. Comparing base (915b591) to head (b3466f3).
✅ All tests successful. No failed tests found.

Additional details and impacted files

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  Coverage    46.0%   46.0%           
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  Files         180     180           
  Lines       14464   14464           
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  Hits         6654    6654           
  Misses       7810    7810           

Flag	Coverage Δ
3.10	46.0% <ø> (ø)
3.11	46.0% <ø> (ø)
3.12	46.0% <ø> (ø)
3.13	45.9% <ø> (ø)
3.14	45.9% <ø> (ø)

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[jluebbe]

Parts of this seem more like a discussion of design decisions and architecture than user documentation "Observed friction in practice", "Why The Current Model Feels Mismatched" and "Possible Improvements". Why is the documentation the appropriate place?

[pamolloy]

Parts of this seem more like a discussion of design decisions and architecture than user documentation "Observed friction in practice", "Why The Current Model Feels Mismatched" and "Possible Improvements". Why is the documentation the appropriate place?

Right, this is trying to frame discussions about how we can address these use cases better in Labgrid. We'll join the call today to discuss further. We wanted to get away from narrow technical discussions to have a broader discussion about how to make Labgrid better for different use cases. And it is difficult to have that discussion if the use cases aren't identified.