chore: remove active_storage_s3 feature flag (#7627)

[Shruti2110-coder]

Description

Removes the active_storage_s3 Flipper feature flag now that the Active Storage migration to S3 is complete and stable in production. Also fully removes the now-unused kt-paperclip gem and all remaining references to Paperclip across the codebase and test suite.

Related Issue

Fixes #7627

Type of Change

• Chore (refactor / cleanup, no functional changes)

Changes Made

• Removed active_storage_s3 entry from config/initializers/flipper.rb
• Removed test setup/teardown referencing the flag in spec/rails_helper.rb
• Removed duplicate specs that only covered the flag-disabled state
• Removed Flipper.disable(:active_storage_s3) calls from API request specs
• Removed the unused kt-paperclip gem from the Gemfile
• Removed dead Paperclip.options[:command_path] config from config/environments/production.rb
• Removed require "paperclip/matchers" and config.include Paperclip::Shoulda::Matchers from spec/spec_helper.rb

How Has This Been Tested?

Full suite: bundle exec rspec — 945 examples, 0 failures, 5 pending (pending specs are pre-existing, unrelated xdescribe-skipped notification specs)

Screenshots (if applicable)

N/A — backend/config cleanup, no UI changes.

Checklist

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have made corresponding changes to the documentation (none needed)
• My changes generate no new warnings
• Existing tests updated/cleaned up to reflect removed flag/gem
• New and existing unit tests pass locally with my changes (945 examples, 0 failures)
• Any dependent changes have been merged and published

AI Declaration

This PR was developed with the assistance of an AI coding assistant (Claude), which helped with:

• Debugging RuboCop lint failures (trailing whitespace/blank lines in spec_helper.rb)
• Resolving the Gemfile.lock merge conflict with upstream/master
• Verifying image upload/Active Storage functionality locally (manual testing walkthrough)

All code changes were reviewed and tested locally by me before pushing.

Summary by CodeRabbit

• Refactor

  • Removed the legacy image attachment dependency and related Paperclip-only test matchers.
  • Stopped enabling the S3-backed image storage feature flag by default.

• Tests

  • Updated controller/request specs to focus on currently supported (feature-enabled) image behavior.
  • Updated RSpec setup to align feature-flag defaults.

• Chores

  • Added Coveralls to the test setup.
  • Cleaned up production configuration formatting.

[coderabbitai]

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Walkthrough

This change removes the active_storage_s3 Flipper feature flag from default and test configuration, along with disabled-path controller and request-spec coverage. It also removes the kt-paperclip dependency and Paperclip matcher setup from test configuration, and deletes a blank line in the production configuration.

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Out of Scope Changes check	⚠️ Warning	The PR also removes Paperclip gem/references and tweaks production config, which are outside #7627.	Move Paperclip cleanup and config-only edits to a separate PR, or add them to the linked issue if intended.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Linked Issues check	✅ Passed	The requested active_storage_s3 flag removal is implemented in app and test setup.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly matches the main change: removing the active_storage_s3 feature flag.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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[tachyons]

Thanks, could you remove paperclip gem as well . Also make sure that you use PR template for description

[Shruti2110-coder]

Hi @tachyons, thanks for the feedback! I've completed both requests
Let me know if there's anything else you'd like adjusted!

[safedep-bot]

vet Summary Report

This report is generated by vet

Policy Checks

• ✅ Vulnerability
• ✅ Malware
• ✅ License
• ✅ Popularity
• ✅ Maintenance
• ✅ Security Posture
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Malicious Package Analysis Report

Ecosystem	Package	Version	Status	Report

• ℹ️ 0 packages have been actively analyzed for malicious behaviour.
• ✅ No malicious packages found.

[tachyons]

• Ensure CI is green
• Follow our PR template with AI declaration
• Run the app locally and verify everything related to image uploads and display without any issues

[Shruti2110-coder]

Hi @tachyons — all set:

• ✅ Lint fixed and CI conflicts resolved (branch shows "Able to merge")
• ✅ Tested image uploads locally — preview generates and displays correctly, no errors in logs
• ✅ Added AI Declaration section to the PR description

CI checks just need workflow approval on your end. Let me know if anything else is needed!

[tachyons]

@Shruti2110-coder could you upload a screencsst showing that image preview upload and profile image upload are working fine and they work in previews including circuitverse contest page ?

[Shruti2110-coder]

Screen.Recording.2026-07-24.at.10.16.57.AM.mov

Screen.Recording.2026-07-24.at.10.20.40.AM.mov

Recorded a walkthrough covering the areas you flagged:

Clip 1: Profile picture upload — working correctly ✅

Clip 2: Contest page — submitted a circuit, thumbnail/preview displays correctly on the contest entries page ✅

Note: I also tested the simulator's Image Annotation upload feature, and it currently fails due to an unrelated pre-existing bug — the hardcoded Imgur API Client-ID is dead/revoked (already tracked in #7342, not caused by this PR).

[tachyons]

Could you fix the merge conflicts