refactor(ui): resolve var declarations and reduce cognitive complexity in pipeline.js

[bhagathkrishnacdac]

Overview
This PR improves the code quality of the pipeline visualization script (bessctl/static/pipeline.js) by modernizing variable declarations and reducing function complexity.

Key Changes

• Modernized Variables: Replaced legacy var declarations with block-scoped const and let keywords.
• Resolved Cognitive Complexity in get_edge_label: Factored out label calculation, scaling, and HTML formatting into specialized helper functions.
• Resolved Cognitive Complexity in graph_to_dot: Refactored DOM option gathering and Graphviz DOT-notation compilation into modular rendering helpers.
• Removed Global State Reliance: Passed the UI option states down explicitly through parameters rather than relying on global variables.

No modifications were made to the visual layout generation, data collection, or UI-bound operations. The generated Graphviz DOT files and label rounding logic match the original behavior.

[Copilot]

Pull request overview

This PR refactors the BESS pipeline visualization script (bessctl/static/pipeline.js) to modernize variable declarations and decompose get_edge_label() and graph_to_dot() into smaller helper functions, with the stated goal of preserving existing rendering/label behavior while reducing complexity.

Changes:

• Replaced legacy var declarations with const/let.
• Split edge-label computation/formatting into helper functions (calculate_*, format_*).
• Refactored DOT generation into modular helpers for option gathering, node generation, and edge generation.

Comments suppressed due to low confidence (1)

bessctl/static/pipeline.js:203

• create_module_node() takes an options parameter but never uses it, and also forwards options into gates_to_str() even though gates_to_str only accepts (gates, gate_type). This makes the data flow harder to follow and can trigger unused-parameter linting. Remove the unused parameter and stop passing it through (and consider also dropping the extra argument at the call site).

function create_module_node(module, module_name, options) {  
    const desc = module.desc ? `<font point-size="9">${module.desc}</font>` : '';  
    // Original gates_to_str might need options
    const igates = module.show_igates ? gates_to_str(module.igates, 'igate', options) : '';  
    const ogates = module.show_ogates ? gates_to_str(module.ogates, 'ogate', options) : '';  

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[gab-arrobo]

I see lots of warnings when applying patch using git. Please address these issues

$ git apply pr.patch
pr.patch:101: trailing whitespace.
function get_edge_label(stats, options) {
pr.patch:102: trailing whitespace.
    if (!stats || stats.length === 0) {
pr.patch:103: trailing whitespace.
        return format_html_label('?');
pr.patch:104: trailing whitespace.
    }
pr.patch:105: trailing whitespace.

warning: squelched 175 whitespace errors
warning: 180 lines add whitespace errors.

[gab-arrobo]

Remove extra empty line

Suggested change

[andybavier]

I've added a "whitespace" CI job that flags whitespace-related formatting issues. To fix the issues with this PR, run "pre-commit run --all-files" locally.