Make clang-tidy CI gate blocking: fix all violations

[lavrovvalera]

Important

Link the implementing PR to this issue by including Closes #<issue_number>
in the PR description or commit message.

What

Remove continue-on-error: true from the QA / Clang-Tidy CI job so that
unresolved clang-tidy violations block PR merges.

The flag was added intentionally when the job was introduced because the codebase
had pre-existing violations. Once all violations tracked in #76, #77, #78, #79
are fixed, this gate can be made blocking.

Acceptance Criteria

• All clang-tidy violations resolved across all components (see Fix SCA and sanitizer findings: score/time #76, Fix SCA and sanitizer findings: score/time_daemon #77, Fix SCA and sanitizer findings: score/time_slave #78, Fix SCA and sanitizer findings: score/ts_client #79)
• continue-on-error: true removed from the clang-tidy job in .github/workflows/clang-tidy.yml
• QA / Clang-Tidy CI job passes without violations on a clean branch

References

• Clang-tidy CI job introduced in: Add Clang-Tidy CI workflow #42
• SCA fix tasks (blockers): Fix SCA and sanitizer findings: score/time #76, Fix SCA and sanitizer findings: score/time_daemon #77, Fix SCA and sanitizer findings: score/time_slave #78, Fix SCA and sanitizer findings: score/ts_client #79