run_before_script: Fix newlines

[tony]

Follow up to #959

Summary by Sourcery

Enhancements:

• Improve performance and provide real-time feedback during run_before_script execution.

[sourcery-ai]

Reviewer's Guide by Sourcery

This pull request refactors the run_before_script function to use chunk-based output, which prevents the function from hanging when the script produces a large amount of output. The original implementation of run_before_script is renamed to run_before_script2.

Sequence diagram for chunk-based script output processing

sequenceDiagram
    participant C as Caller
    participant R as run_before_script
    participant P as subprocess.Popen
    participant O as stdout
    participant E as stderr

    C->>R: run_before_script(script_file, cwd)
    R->>P: Create process
    activate P
    loop Until process ends
        R->>P: poll()
        R->>O: read(1024)
        alt has output
            O-->>R: chunk
            R->>R: buffer chunk
            R->>R: write to stdout if TTY
        end
        R->>E: read(1024)
        alt has error output
            E-->>R: chunk
            R->>R: buffer chunk
            R->>R: write to stderr if TTY
        end
    end
    R->>P: wait()
    P-->>R: return code
    alt return code != 0
        R->>R: raise BeforeLoadScriptError
    end
    R-->>C: return code
    deactivate P

Loading

File-Level Changes

Change	Details	Files
Refactor run_before_script to use chunk-based output.	The original implementation of run_before_script is renamed to run_before_script2. The new run_before_script reads stdout and stderr in chunks of 1024 bytes. The new run_before_script writes stdout and stderr to the terminal as it receives data. The new run_before_script uses a loop to read from the subprocess until it exits.	src/tmuxp/util.py

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[sourcery-ai]

Hey @tony - I've reviewed your changes - here's some feedback:

Overall Comments:

• The old implementation should be removed rather than kept as run_before_script2. Having both versions will create confusion and maintenance overhead.

Here's what I looked at during the review

• 🟢 General issues: all looks good
• 🟢 Security: all looks good
• 🟢 Testing: all looks good
• 🟡 Complexity: 1 issue found
• 🟢 Documentation: all looks good

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[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 73.11%. Comparing base (001b85c) to head (99f0354).

Additional details and impacted files

@@           Coverage Diff           @@
##           master     #960   +/-   ##
=======================================
  Coverage   73.11%   73.11%           
=======================================
  Files          26       26           
  Lines        1856     1856           
  Branches      352      352           
=======================================
  Hits         1357     1357           
  Misses        395      395           
  Partials      104      104           

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