QVAC-18954: bump qvac-lib-inference-addon-cpp to 1.2.0 across addons

[jpgaribotti]

🎯 What problem does this PR solve?

• The CI linting step currently fails due to code that has drifted while the check was disabled.
• New stricter string api conventions require a transparent string map to avoid many cases of avoidable temporary std::string materialization.

📝 How does it solve it?

• Bumps qvac-lib-inference-addon-cpp constraint from 1.1.7#1 to 1.2.0 in addon vcpkg.json files on origin/addon-lint. This version simplifies linting checks to just naming and provides the TransparentStringMap type.
• Applies the same version floor consistently across:
  • bci-whispercpp, classification-ggml, diffusion-cpp, embed-llamacpp, llm-llamacpp, ocr-onnx, transcription-parakeet, transcription-whispercpp, translation-nmtcpp, tts-ggml, tts-onnx.

🧪 How was it tested?

• Verified remote branch diff scope with main...origin/addon-lint (single commit, dependency-constraint-only changes).
• No additional functional/source-code changes included in the remote commit.

[jpgaribotti]

/review

[github-actions]

Tier-based Approval Status

**PR Tier:** TIER1

**Current Status:** ✅ APPROVED

**Requirements:**
- 1 Team Member approval ❌ (0/1)
- 1 Team Lead OR Management approval ✅ (3/1)

**Bypass rule:** Triggered (2+ Team Lead approvals (Tier 1 exception)). This PR is approved regardless of tier.

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*This comment is automatically updated when reviews change.*