feat(cpp): Add bazel building and testing infrastructure

[slbotbm]

Which issue does this PR close?

Closes #2762

Rationale

What changed?

Adds bazel build system + stub classes and their tests + ci scripts

Local Execution

• Passed
• Pre-commit hooks ran

AI Usage

If AI tools were used, please answer:

1. Which tools? codex
2. Scope of usage? build system implementation
3. How did you verify the generated code works correctly? checking on local environment
4. Can you explain every line of the code if asked? Yes

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 68.02%. Comparing base (28e7c04) to head (0f7d778).
⚠️ Report is 19 commits behind head on master.

Additional details and impacted files

@@             Coverage Diff              @@
##             master    #2785      +/-   ##
============================================
- Coverage     68.44%   68.02%   -0.43%     
- Complexity      656      739      +83     
============================================
  Files           852      874      +22     
  Lines         68196    69810    +1614     
  Branches      59657    60434     +777     
============================================
+ Hits          46679    47489     +810     
- Misses        19187    19972     +785     
- Partials       2330     2349      +19     

Flag	Coverage Δ
csharp	67.06% <ø> (-0.21%)	⬇️
java	54.83% <ø> (+2.64%)	⬆️
python	0.00% <ø> (?)
rust	69.69% <ø> (+0.08%)	⬆️

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see 71 files with indirect coverage changes

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[atharvalade]

Nice work on the infra setup. the CI integration and Bazel config are clean.

Two things to fix before merge though: the Expiry class in iggy.hpp has all its getters (expiry_type(), expiry_value(), value()) under private: unlike the other three classes, so it's completely opaque after construction (and the test can only SUCCEED() without asserting anything). Also, the genrule srcs hard-codes just src/lib.rs as soon as a second .rs file is added, Bazel won't detect changes to it and will serve stale cached builds. Swapping to glob(["src/**/*.rs"]) should fix that.

[slbotbm]

@atharvalade thanks for the review! those were some things that had been left over from when I was experimenting with the public interface. I've standardized all of the getter functions and corrected the bazel build file as well.

[slbotbm]

@hubcio Thanks for the review. I'll address the other two comments after thinking about the best approach

[hubcio]

still not properly fixed. you need to call clang-format-18, because if it was installed it'll use system version.