feat(skills): add installer execution stub command

src/cli/skills.ts

@@ -38,6 +38,13 @@ export interface SkillInstallPreflightView {
   skipped: SkillInstallerPlanView['skipped'];
 }
 
+export interface SkillInstallerExecutionStubView {
+  skill: SkillInstallerPlanView['skill'];
+  execution: 'stub';
+  wouldRun: string[];
+  skipped: SkillInstallerPlanView['skipped'];
+}
+
 export function toSkillListRows(skills: Skill[]): SkillListRow[] {
   return skills
     .map((skill) => ({
@@ -196,6 +203,41 @@ export function renderSkillInstallPreflight(view: SkillInstallPreflightView): st
   return lines.join('\n');
 }
 
+export function toSkillInstallerExecutionStubView(skill: Skill): SkillInstallerExecutionStubView {
+  const plan = toSkillInstallerPlanView(skill);
+  return {
+    skill: plan.skill,
+    execution: 'stub',
+    wouldRun: plan.steps.map((step) => step.command),
+    skipped: plan.skipped,
+  };
+}
+
+export function renderSkillInstallerExecutionStub(view: SkillInstallerExecutionStubView): string {
+  const lines: string[] = [
+    `Installer execution stub for '${view.skill.name}' (${view.skill.tier}, v${view.skill.version})`,
+    'No installer commands were executed.',
+  ];
+
+  if (view.wouldRun.length === 0) {
+    lines.push('Would run: none');
+  } else {
+    lines.push('Would run:');
+    for (const command of view.wouldRun) {
+      lines.push(`- ${command}`);
+    }
+  }
+
+  if (view.skipped.length > 0) {
+    lines.push('Skipped:');
+    for (const skip of view.skipped) {
+      lines.push(`- [${skip.installerType}] ${skip.reason}`);
+    }
+  }
+
+  return lines.join('\n');
+}
+
 export function summarizeSkillsRefresh(skills: Skill[]): SkillRefreshSummary {
   const summary: SkillRefreshSummary = {
     total: skills.length,
@@ -495,4 +537,33 @@ export function registerSkillsCommand(program: Command): void {
 
       console.log(renderSkillInstallerPlan(view));
     });
+
+  skills
+    .command('execute <name>')
+    .description('Preview installer execution steps (stub only; no commands run)')
+    .option('--json', 'Output as JSON')
+    .option('-c, --config <path>', 'Config file path')
+    .action((name: string, opts: { json?: boolean; config?: string }) => {
+      const loaded = loadSkillsFromConfig(opts.config);
+      if (loaded.error || !loaded.skills) {
+        console.error(loaded.error ?? 'Failed to load skills');
+        process.exitCode = 1;
+        return;
+      }
+
+      const skill = loaded.skills.find((item) => item.manifest.name === name);
+      if (!skill) {
+        console.error(`Skill '${name}' not found.`);
+        process.exitCode = 1;
+        return;
+      }
+
+      const view = toSkillInstallerExecutionStubView(skill);
+      if (opts.json) {
+        console.log(JSON.stringify(view, null, 2));
+        return;
+      }
+
+      console.log(renderSkillInstallerExecutionStub(view));
+    });
 }