Refactor and Finalize Session Tracking (Building on closed unmerged #74)

[rammakablecode]

Description

This PR integrates and corrects the session tracking logic for the 10.0.x branch. It uses the service-layer approach originally proposed in PR #74, while addressing missing schema definitions and environment blockers currently on 10.0.x.

During testing, I identified issues that blocked development and limited the usefulness of the existing schema:

• MySQL tablespace errors (errno: 194) prevented successful migrations in Windows-hosted Docker environments.
• CRLF line endings in shell scripts caused Dev Container startup failures.
• The frontend would have to fetch every session_activity timestamp and compute gaps client-side, which is inefficient and complex.

To resolve these, this PR:

• Fixes the migration sequence to avoid tablespace issues.
• Standardizes shell scripts to LF line endings for Docker compatibility.
• Adds a duration_minutes column to the marking_sessions table, allowing session durations to be calculated and aggregated directly in the backend.

Frontend impact
Persisting duration_minutes enables direct aggregation via the API and removes the need for complex time-delta calculations in the Angular frontend. This change is intended to support(thoth-tech/doubtfire-web#402). By providing this data via the API, we avoid complex time-delta calculations in the Angular frontend, allowing 402 to be refactored to connect directly to this backend logic since the frontend contributions are yet to connect to exisitng backend.

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)

How Has This Been Tested?

• Test A: Migration Sequence
  Executed bundle exec rails db:migrate:redo VERSION=20250922103033.

  Verified:
  marking_sessions table is created successfully
  duration_minutes column exists
  No MySQL tablespace errors occur

• Test B: Session Tracking Logic
  Ran bundle exec ruby -I test test/services/session_tracker_test.rb.
  Result: 2 runs, 13 assertions, 0 failures, 0 errors.

  Confirmed:
  15-minute "sticky" session window works
  duration_minutes is correctly updated upon activity.

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• My changes generate no new warnings
• New and existing unit tests pass locally with my changes

[SteveDala]

@rammakablecode please change the base of this pull request to be thoth-tech:10.0.x.

[rammakablecode]

Changed base @SteveDala thank you for that catch!