refactor: use a task type table instead of a column

[ethanholz]

This PR closes #49 . This model was originally used in the benchmarking_orchestration project. For more information on the original implementation see here: https://github.com/omsf-eco-infra/benchmarking-orchestration/blob/51200f79f1d220c1253d869a0018b322dedad301/src/benchmarking_orchestration/tasks/__init__.py#L53-L134

This code was slimmed down and implemented partially by me and 152de01 was created using an agent with direction from my first commit. It is important to note that this is a breaking change because it removes the task type column but this change is optional for all but any clients who may have used exorcist in the last week (this is of little concern).

Assisted-by: Pi:openai-codex/gpt-5.6-sol

[codecov]

Codecov Report

❌ Patch coverage is 92.30769% with 4 lines in your changes missing coverage. Please review.
✅ Project coverage is 98.90%. Comparing base (9cfe24e) to head (a375da5).

Files with missing lines	Patch %	Lines
exorcist/taskdb.py	91.42%	3 Missing ⚠️
exorcist/tests/test_taskstatusdb.py	94.11%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #53      +/-   ##
==========================================
- Coverage   99.06%   98.90%   -0.16%     
==========================================
  Files           6        6              
  Lines         532      548      +16     
==========================================
+ Hits          527      542      +15     
- Misses          5        6       +1     

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