Phase 3: Add Self type annotations to fluent/clone methods

[Balandat]

Summary:
Add Self type annotation from typing module to methods that return self
or cloned instances of the same class. This enables better type inference
for subclasses and improves IDE support.

Files changed:

• ax/core/base_trial.py - run(), stop(), complete(), mark_*() methods
• ax/core/batch_trial.py - mark_arm_abandoned()
• ax/core/experiment.py - add_tracking_metric(), update_tracking_metric(), etc.
• ax/core/multi_type_experiment.py - add_trial_type(), update_runner(), metric methods
• ax/core/arm.py - clone()
• ax/core/objective.py - clone() on Objective, MultiObjective, ScalarizedObjective
• ax/core/optimization_config.py - clone()
• ax/core/runner.py - clone()
• ax/core/parameter.py - clone() abstract method

Differential Revision: D93186334

[meta-codesync]

@Balandat has exported this pull request. If you are a Meta employee, you can view the originating Diff in D93186334.

[codecov-commenter]

Codecov Report

❌ Patch coverage is 97.50000% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 96.80%. Comparing base (5f8d82a) to head (98d6b20).

Files with missing lines	Patch %	Lines
ax/core/multi_type_experiment.py	85.71%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #4907      +/-   ##
==========================================
- Coverage   96.80%   96.80%   -0.01%     
==========================================
  Files         595      595              
  Lines       63143    63148       +5     
==========================================
+ Hits        61127    61131       +4     
- Misses       2016     2017       +1     

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[meta-codesync]

This pull request has been merged in ff18218.