Run the browser in IST so Aquilaehr Visit Dates are not shifted a day

Aquilaehr's Export CSV is built in the browser and converts Visit Date to
the browser timezone. On the server (TZ=America/New_York) every visit came
out one day early, so Alpha matched 11 of 214 instead of 190.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

Dockerfile

@@ -12,7 +12,8 @@ RUN pip install --no-cache-dir -r requirements.txt
 COPY . .
 
 # headless, system Chromium (Playwright's own browser download is not used)
-ENV HEADLESS=1 CHROME_PATH=/usr/bin/chromium PYTHONUNBUFFERED=1 TZ=America/New_York
+# TZ: IST like the team's PCs (also what the browser uses, see BROWSER_TZ in mek_recon.py)
+ENV HEADLESS=1 CHROME_PATH=/usr/bin/chromium PYTHONUNBUFFERED=1 TZ=Asia/Kolkata
 EXPOSE 8000
 # one worker: run state is kept in memory
 CMD ["gunicorn", "-w", "1", "--threads", "8", "-b", "0.0.0.0:8000", "--timeout", "120", "app:app"]