Replace pytz with standard library zoneinfo

[Copilot]

Removes pytz dependency in favor of Python 3.9+ standard library zoneinfo module.

Changes

Core replacements:

• pytz.timezone() → ZoneInfo()
• pytz.utc → timezone.utc
• pytz.UnknownTimeZoneError → ZoneInfoNotFoundError
• tzinfo.localize(dt) → dt.replace(tzinfo=tzinfo)

Files modified:

• Source: utils.py, app.py, render/glyph.py, render/attime.py
• Tests: test_attime.py, test_functions.py
• Config: pyproject.toml, docs/conf.py

Example

# Before
import pytz
tzinfo = pytz.timezone('America/Los_Angeles')
dt = tzinfo.localize(datetime.strptime(time_string, '%H:%M%Y%m%d'))

# After
from zoneinfo import ZoneInfo
tzinfo = ZoneInfo('America/Los_Angeles')
dt = datetime.strptime(time_string, '%H:%M%Y%m%d').replace(tzinfo=tzinfo)

All 486 tests pass.

Original prompt

Replace pytz with standard library code

---

💡 You can make Copilot smarter by setting up custom instructions, customizing its development environment and configuring Model Context Protocol (MCP) servers. Learn more Copilot coding agent tips in the docs.