ci: consume platform workflows v1

[Matheus-TecDev]

Migrates Sentinel to the stable v1 alias of the reusable platform workflows.

• updates Python API and React Web CI references;
• updates the Security Scan reference;
• updates both Docker Publish references;
• preserves events, permissions, inputs and existing workflow behavior.

Validation:

• exactly five references now use @v1;
• no previous SHA references remain;
• only reusable workflow uses were changed;
• all modified YAML files are valid;
• Docker Publish remains validation-only on pull requests.