refactor: split `tc.rs` for each command

[beelchester]

Summary:
Refactor tc.rs into a module and create separate files for the commands.

Issue Reference(s):
Fixes #2281 /claim #2281

Build & Testing:

• [x] I ran cargo test successfully.
• [x] I have run ./lint.sh --mode=fix to fix all linting issues raised by ./lint.sh --mode=check.

Checklist:

• [x] I have performed a self-review of my code.
• [x] PR follows the naming convention of <type>(<optional scope>): <title>

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[codecov[bot]]

Codecov Report

Attention: Patch coverage is 0% with 170 lines in your changes missing coverage. Please review.

Project coverage is 85.70%. Comparing base (fadea96) to head (3d013c9).

Files	Patch %	Lines
src/cli/tc/init.rs	0.00%	69 Missing :warning:
src/cli/tc/run.rs	0.00%	34 Missing :warning:
src/cli/tc/check.rs	0.00%	26 Missing :warning:
src/cli/tc/helpers.rs	0.00%	24 Missing :warning:
src/cli/tc/start.rs	0.00%	11 Missing :warning:
src/cli/tc/gen.rs	0.00%	6 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #2286 +/- ## ========================================== - Coverage 85.79% 85.70% -0.09% ========================================== Files 227 232 +5 Lines 21957 21979 +22 ========================================== Hits 18837 18837 - Misses 3120 3142 +22 ```

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