Suppress verbose tracebacks by default, show only with -vv

[Copilot]

Describe your changes

Unhandled exceptions currently dump full Python stack traces, burying the actual error message in noise. This installs a custom sys.excepthook in the fre() entry point that shows only the error type and message at default/-v verbosity, with a hint to use -vv for the full traceback.

Before (default):

clone of FMSpid exited with status 128
Traceback (most recent call last):
  File "...", line 8, in <module>
    sys.exit(fre())
  ... (20+ lines of click internals) ...
subprocess.CalledProcessError: Command '...' returned non-zero exit status 128.

After (default):

CalledProcessError: Command '...' returned non-zero exit status 128.
(use 'fre -vv ...' for the full traceback)

After (fre -vv): full traceback, same as current behavior.

Changes:

• fre/fre.py: Set sys.excepthook to a brief formatter when log_level > DEBUG. Updated -v help text.
• fre/tests/test_fre_cli.py: Three subprocess-based tests covering default, -v, and -vv traceback behavior.
• docs/tools.rst: Document traceback suppression under the -v[v] flag.

Issue ticket number and link (if applicable)

Checklist before requesting a review

• I ran my code
• I tried to make my code readable
• I tried to comment my code
• I wrote a new test, if applicable
• I wrote new instructions/documentation, if applicable
• I ran pytest and inspected it's output
• I ran pylint and attempted to implement some of it's feedback
• No print statements; all user-facing info uses logging module

[codecov]

Codecov Report

❌ Patch coverage is 66.66667% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 84.10%. Comparing base (836559e) to head (cf83c57).
⚠️ Report is 10 commits behind head on main.

Files with missing lines	Patch %	Lines
fre/fre.py	66.66%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #852      +/-   ##
==========================================
- Coverage   84.12%   84.10%   -0.03%     
==========================================
  Files          71       71              
  Lines        4944     4950       +6     
==========================================
+ Hits         4159     4163       +4     
- Misses        785      787       +2     

Flag	Coverage Δ
unittests	84.10% <66.66%> (-0.03%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files with missing lines	Coverage Δ
fre/fre.py	94.44% <66.66%> (-5.56%)	⬇️

---

Continue to review full report in Codecov by Sentry.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 836559e...cf83c57. Read the comment docs.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.