MOD-14470 Add VecSimParams_GetQueryBlobSize API for safe query vector allocatio

[meiravgri]

Adds a new public API function VecSimParams_GetQueryBlobSize(type, dim, metric) to calculate the required buffer size for query vectors that will be normalized via VecSim_Normalize.

Background

When normalizing INT8/UINT8 vectors with Cosine metric, VecSim_Normalize appends the vector's norm (a float) at the end of the blob. Callers allocating buffers for query vectors need to account for this extra space to avoid buffer overflows.

This API encapsulates the sizing logic so callers don't need to know the internal implementation details of how normalization works for different type/metric combinations.

Main objects this PR modified

• src/VecSim/vec_sim.h - Added declaration and documentation for VecSimParams_GetQueryBlobSize
• src/VecSim/vec_sim.cpp - Added implementation of VecSimParams_GetQueryBlobSize

Mark if applicable

[X] This PR introduces API changes
[ ] This PR introduces serialization changes

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Note

Low Risk
Small, additive API plus tests; behavior is straightforward and only influences callers that opt into the new helper.

Overview
Adds a new public API VecSimParams_GetQueryBlobSize(type, dim, metric) to let callers allocate query-vector buffers safely when using VecSim_Normalize, including the extra float norm appended for INT8/UINT8 under Cosine metric.

Extends unit coverage with a parameterized test for the new sizing logic, and hardens CommonTypeMetricTests teardown to avoid freeing a null index.

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[jit-ci]

🛡️ Jit Security Scan Results

✅ No security findings were detected in this PR

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^{Security scan by Jit}

[cursor]

Cursor Bugbot has reviewed your changes and found 1 potential issue.

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 97.11%. Comparing base (586a220) to head (e657913).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #915      +/-   ##
==========================================
- Coverage   97.13%   97.11%   -0.03%     
==========================================
  Files         129      129              
  Lines        7551     7557       +6     
==========================================
+ Hits         7335     7339       +4     
- Misses        216      218       +2     

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[ofiryanai]

overall fine, one suggestion. ping to reapprove if you decide to change it