Feat: Updated backend with health checks and current stage we're processing in status, updated frontend with progress bar

[Vchen7629]

• tests(backend): updated pipeline tests to test the new code
• tests(backend): uncommented idempotency e2e tests in pipeline-tests
• fix(scene-detector): added kv with checks to fix idempotency issues on duplicate messages pubed
• tests(scene-detector): added tests to test the new kv code
• chore(scene-detector): reduced KV TTL from 7 days to 3 hours
• feat(transcoder-worker): created idempotency kv helper functions
• feat(transcoder-worker): updated subscriber.go with the idempotency KV check and add
• feat(transcoder-worker): updated main.go to create the idempotency kv
• fix(transcoder-worker): fixed fmt error formatting in chunk_kv.go
• chore(transcoder-worker): updated error msgs
• tests(transcoder-worker): created unit/integration tests for chunk_kv.go and updated subscriber and main.go
• tests(backend): added idempotency pipeline tests for all 3 services
• fix(transcoder-worker): added missing nak for get unprocessed video chunk in subscriber.go
• feat(video-recombiner): added kv for idempotency
• tests(video-recombiner): added extra integration/unit tests for subscriber.go and main.go
• fix(video-upload): added missing ttl to KV
• tests(transcoder-worker): updated subscriber unit test
• fix(video-status): changed port from 8081 to 8085 to avoid port conflict with seaweedfs
• refactor(transcoder-worker): extracted kv related logic into handler package job_status_kv.go
• feat(transcoder-worker): updated subscriber.go to update the job status kv with the current stage for frontend progress bar
• refactor(transcoder-worker): extracted structured logger into observability package
• fix(video-upload): change the kv creation to connect since video-status precreates the video-status KV
• feat(video-recombiner): added job_status_kv.go so it can update the job status KV with current stage
• feat(video-recombiner): added http service for health checks to check if service is degraded
• feat(scene-detector): updated subscriber.py to write the job status kv and rename folder from nats to handler
• feat(scene-detector): created http_server.py to initialize an health endpoint for video-status degrade checks
• chore(scene-detector): updated job.py import
• feat(scene-detector): updated service.py to register the health endpoint and added connection to the job status KV
• feat(video-recombiner): updated subscriber.go to update the job status KV
• feat(video-status): added http health checks on each service and added degraded state
• fix(video-status): added missing err checks
• tests(video-status): created/updated unit/integration tests for the handler package
• tests(video-status): created/updated unit/integration tests for the handler package
• refactor(transcoder-worker): moved startHttpServer to handler package and create ShutdownHttpServer function
• fix(transcoder-worker): changed logger name to be correct
• fix(transcoder-worker): added missing return to ConnectJobStatusKV and CreateMsgProcessedKV
• tests(transcoder-worker): added additional unit/integration tests
• refactor(video-recombiner): moved http server start and shutdown to handler package
• tests(video-recombiner): updated unit/integration tests to test updated code
• tests(scene-detector): updated unit/integration tests to work with updated code, simplified existing tests by extracting duplicate logic in reusable helpers/fixtures
• feat(frontend): updated video upload list to show the progress bar with stage context