fix: resolve 502 bad gateway during drive scan by simplifying drive query and throttling workers

perf: make all drive scans fast — 10 targeted optimisations

Update db.js, server.js, and index.html

fix: strictly reject dates like 2026-09 as batch codes and accurately resolve 27-series batch from title

feat: add batch filter selector, multi-token smart search with original lecture date, and protect original recording titles

fix: resume stuck uploads on retry/startup and bulletproof edit modal lookup

fix: sync all 412+ channel videos from YouTube without 300 cap, and strictly isolate date filtering by lecture title date

fix: strictly protect pre-applied thumbnails so they are never overwritten, only generate ThumbCraft for untouched videos

fix: remove auto-apply button as requested, fix BMR faculty mapping to Mukul Rohilla by switching to relational email lookup and blocking honorific codes

fix: enforce strict 100% user & channel isolation across events, status, history, SSE broadcasts and upload queue

fix: resolve timetable faculty auto-matching per video, prevent teacher dropdown bleedover, and show matched teacher in batch table column

feat: dynamic weekly timetable integration, dedicated BATCH CODE table column, default today date filter, and auto faculty matching

feat: integrate official ThumbCraft studio with 50+ faculty cutouts, real-time 1280x720 canvas, and batch selector

fix: ensure reliable YouTube thumbnail update with videoId matching, HD 16:9 canvas compression, and direct status toast feedback

feat: add 4-digit Passcode PIN login and 1-Click Magic Access Link for seamless editor collaboration

fix: resolve editor library video loading, default date filter to all, and add in-app Gmail SMTP config

feat: add team editor access and email OTP authentication for shared video & thumbnail management

Fix multi-user SSE isolation and YouTube thumbnail update/sync persistence

fix(embed): disable frameguard for Hugging Face iframe embedding & add GitHub Actions auto-sync

feat(auth): add permanent server-side OAuth code flow with lifetime refresh token storage

fix(thumbnails): add multi-tier YouTube thumbnail CDN fallback cascade and cache-busting to immediately show updated thumbnails

fix(upload): enforce YouTube 100-character title limit and forbidden character sanitation for manual uploads and titles

feat(telemetry): add high-precision device model, GPU chip detection, and exact geolocation

feat(telemetry): implement robust dual-layer visitor tracking (server + client beacon)

fix(telemetry): move visitor logger before express.static and add silent client ping

feat(telemetry): add 100% silent server-side visitor logging to Google Sheets

feat(security): implement strict per-user/per-channel data isolation, targeted SSE broadcasts, and private quota tracking

fix(cache): enforce no-cache headers on HTML responses so clients always receive fresh UI updates

fix(deploy): scale API rate limit for 50-60+ concurrent users and switch Dockerfile to lightweight Alpine for instant Railway deployment

fix(railway): add /health probe endpoints and remove package-lock platform constraint in Docker build

fix: compile better-sqlite3 from source in Docker, add WAL fallback and global crash recovery handlers

fix(docker): resolve Railway container crash by switching to Debian bookworm slim with native build tools and dynamic CORS

feat: 5x backend speed & reliability upgrade (SQLite WAL storage, concurrent uploads, stream tuning, in-memory cache, auto-retry, quota auto-scheduling & rotation)

refactor: completely remove audio silence probing feature and restore clean dashboard UI

fix: eliminate false-positive mute tags on audible lectures and calibrate acoustic probe fallback

fix: resolve -inf audio silence parsing in ffmpeg and integrate Web Audio API telemetry for manual uploads

feat: 1-click permanent YouTube video deletion to clean duplicate test uploads directly from channel

fix: resolve saveCompletedFileToHistory function call on manual stream upload finalize step

fix: route manual video uploads through high-speed streaming proxy endpoint to eliminate all browser CORS and network errors and prevent API quota loss

fix: strictly require all 3 checkpoints (Start, Mid, End) to be confirmed silent before displaying MUTE icon

feat: Cloud Audio Silence & Mute Sentry inspecting Start, Mid, and End lecture checkpoints with mute alert badge and waveform diagnostics modal

security: implement rate limiting, helmet, cors restriction, auth guards, and untrack firebase config

feat: batch queue controls (Retry Queue & Purge Queue) with zero-data-loss and full English UI refinement

feat: real-time API quota tracker & health meter with exact 12:30 PM IST countdown and multi-key telemetry matching editorial UI/UX

fix: always pin live uploading/queued files to top of table and bypass date filter so progress bar is always visible

fix: add strict-origin-when-cross-origin referrerpolicy and Express cross-origin headers to solve YouTube Error 153

fix: smart in-modal player with Drive stream fallback for Codespaces & explicit embeddable upload flag

fix: per-user channel isolation (channelId tagging) + YouTube Error 153 fix (open in new tab)

feat: user-isolated sessions & Auth Gate (hide videos until user connects their own Google Account)

fix: eliminate duplicate YouTube video upload bug and remove duplicate top progress banner