tz_issue_fix

[Ajay-Satish-01]

Description

Solves #5673

• Adds timezone-aware parsing for relative CLI/API start, end, and execution-time values (e.g. --start "2 weeks ago"), anchored to local calendar-day midnight in a configured IANA timezone instead of UTC.
• --time-zone CLI flag on plan, render, evaluate, run, audit, and check_intervals (overrides config)
  time_zone config (optional, IANA-validated; UTC is treated as unset)
• Precedence: CLI > config > UTC
• Relative parsing: day-or-larger relatives ("1 week ago", "today", etc.) use local midnight in the configured zone; sub-day relatives ("2 hours ago") are unchanged
• Macro variables: @start_tstz / @end_tstz reflect the correct UTC instant; @start_ds / @end_ds use the local calendar date only when bounds came from relative strings (via localize_start_ds / localize_end_ds); incremental backfill intervals keep UTC-based @start_ds / @end_ds
• Docs updated in macro_variables.md
• Java 24+ Spark: skip @pytest.mark.pyspark tests and raise a clear ConfigError when Spark cannot start on unsupported JDK versions

Test Plan

• pytest tests/utils/test_date.py — relative parsing (LA/Tokyo), date_dict, DST spring/fall-back, hour-grain ignores timezone, interval bounds stay UTC, absolute dates stay UTC
• pytest tests/core/test_context.py -k "time_zone or render_relative or render_absolute or backfill_uses_utc or plan_rejects_invalid"
• pytest tests/core/test_plan.py::test_plan_relative_dates_with_time_zone
• pytest tests/core/test_config.py::test_config_time_zone
• pytest tests/cli/test_cli.py::test_plan_accepts_time_zone_option tests/cli/test_cli.py::test_plan_rejects_invalid_time_zone
• pytest tests/integrations/jupyter/test_magics.py::test_evaluate — Jupyter magic with no execution_time
• pre-commit run mypy --all-files
• PySpark tests skip cleanly on Java 24+ (local Java 26 verified)

Checklist

• I have run make style and fixed any issues
• I have added tests for my changes (if applicable)
• All existing tests pass (make fast-test)
• My commits are signed off (git commit -s) per the DCO

[Ajay-Satish-01]

@StuffbyYuki, please review this PR and let me know if anything is required