refactor(skills): modularize generated skill template and improve env handling

[twishabansal]

Description

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impact, along with a summary of the solution

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🛠️ Fixes #<issue_number_goes_here>

[gemini-code-assist]

Code Review

This pull request refactors the generated script template in generator.go by modularizing the environment setup and execution logic into mergeEnvVars, prepareEnvironment, and main functions. It also updates the test suite and changes the mode identifier from 'binary' to 'bin'. A critical scope error was identified in the refactored template where the child process variable was declared using const inside conditional blocks, making it inaccessible to event listeners. The reviewer provided a suggestion to fix this by using function-scoped declaration and corrected inconsistent indentation throughout the template.

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cmd/internal/skills/generator.go (137-232)

The refactored script template has two significant issues:

1. Scope Error (Critical): The child variable is declared using const inside the if and else blocks of the template. Since const is block-scoped in JavaScript, the child variable is not accessible outside of those blocks (e.g., at line 222). This will result in a ReferenceError: child is not defined when the script is executed.
2. Inconsistent Indentation (Medium): The template content mixes tabs and spaces, and the indentation levels are inconsistent (e.g., jumping from 1 tab to 3 tabs, or mixing 4 spaces with tabs). For the embedded JavaScript, it is recommended to use a consistent indentation style (e.g., 4 spaces).

I have provided a suggestion that fixes the scope issue by declaring let child at the top of the main() function and cleans up the indentation throughout the template.

function mergeEnvVars(env) {
    const envPath = path.resolve(__dirname, '../../../.env');
    if (fs.existsSync(envPath)) {
        const envContent = fs.readFileSync(envPath, 'utf-8');
        envContent.split('\n').forEach(line => {
            const trimmed = line.trim();
            if (trimmed && !trimmed.startsWith('#')) {
                const splitIdx = trimmed.indexOf('=');
                if (splitIdx !== -1) {
                    const key = trimmed.slice(0, splitIdx).trim();
                    let value = trimmed.slice(splitIdx + 1).trim();
                    value = value.replace(/(^['"]|['"]$)/g, '');
                    if (env[key] === undefined) {
                        env[key] = value;
                    }
                }
            }
        });
    }
}

function prepareEnvironment() {
    let env = { ...process.env };
    let userAgent = "skills";
    if (process.env.GEMINI_CLI === '1') {
        userAgent = "skills-geminicli";
        mergeEnvVars(env);
    }
    {{if .OptionalVars}}
    OPTIONAL_VARS_TO_OMIT_IF_EMPTY.forEach(varName => {
        if (env[varName] === '') {
            delete env[varName];
        }
    });
    {{end}}

    return { env, userAgent };
}

/**
 * Main execution function.
 */
function main() {
    const { env, userAgent } = prepareEnvironment();
    const args = process.argv.slice(2);
    let child;

    {{if eq .InvocationMode "npx"}}
    const command = os.platform() === 'win32' ? 'npx.cmd' : 'npx';
    const processedArgs = os.platform() === 'win32' ? args.map(arg => arg.includes('"') ? '"' + arg.replace(/"/g, '""') + '"' : arg) : args;
    const npxArgs = ["--yes", "@toolbox-sdk/server@{{.ToolboxVersion}}", "--log-level", "error", ...configArgs, "invoke", toolName, "--user-agent-metadata", userAgent, ...processedArgs];

    child = spawn(command, npxArgs, { shell: os.platform() === 'win32', stdio: 'inherit', env });
    {{else}}
    function getToolboxPath() {
        if (process.env.GEMINI_CLI === '1') {
            const ext = process.platform === 'win32' ? '.exe' : '';
            const localPath = path.resolve(__dirname, '../../../toolbox' + ext);
            if (fs.existsSync(localPath)) {
                return localPath;
            }
        }
        try {
            const checkCommand = process.platform === 'win32' ? 'where toolbox' : 'which toolbox';
            const globalPath = execSync(checkCommand, { stdio: 'pipe', encoding: 'utf-8' }).trim();
            if (globalPath) {
                return globalPath.split('\n')[0].trim();
            }
            throw new Error("Toolbox binary not found");
        } catch (e) {
            throw new Error("Toolbox binary not found");
        }
    }

    let toolboxBinary;
    try {
        toolboxBinary = getToolboxPath();
    } catch (err) {
        console.error("Error:", err.message);
        process.exit(1);
    }

    const toolboxArgs = ["--log-level", "error", ...configArgs, "invoke", toolName, "--user-agent-metadata", userAgent, ...args];
    child = spawn(toolboxBinary, toolboxArgs, { stdio: 'inherit', env });
    {{end}}

    child.on('close', (code) => {
        process.exit(code);
    });

    child.on('error', (err) => {
        console.error("Error executing toolbox:", err);
        process.exit(1);
    });
}

main();

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