Fix missing dependencies and git staging rule in UI test analysis jobs

Added missing dependencies:
- Java 21 setup (required for compilation verification)
- FFmpeg installation (required for ffprobe video analysis)

Added critical git staging rule to all UI test workflows:
- NEVER use `git add -A` or `git add .` when creating fix branches
- Always add modified files explicitly by path
- This prevents accidentally staging unrelated files that could cause
  push failures due to GitHub App workflow permission restrictions

Affected workflows:
- runUiTestsIJ.yml (unified IntelliJ IDEA tests)
- runUiPyTests.yml (PyCharm macOS tests)
- runUiPyTestsLinux.yml (PyCharm Linux tests)
- runUiRdTests.yml (Rider macOS tests)
- runUiRdTestsLinux.yml (Rider Linux tests)
- runUiOctopusTests.yml (Non-Octopus tests)

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>