Update embedded K10 pH titrator project

[rockets-cn]

Summary

• replace the earlier k10-ph-titrator/ snapshot with the latest project from codex/ph-titrator
• preserve the K10 project as a self-contained subdirectory alongside the existing OpenTitrator application
• include the latest firmware, authentication, web UI, tests, documentation, and mechanical model

Validation

• PlatformIO unihiker build passed
• PlatformIO unihiker-auth-recovery build passed with temporary generated credentials
• 16 Python unit tests passed
• PowerShell OTA, authentication, safety, and bilingual UI tests passed
• Node.js curve replay and IndexedDB tests passed
• native C++ tests were not run locally because no host C++ compiler was installed

Note

• k10-ph-titrator/mechanical/ph_titrator.step is 52.45 MB; GitHub accepted it but recommends Git LFS for files over 50 MB