refactor: preamble, co-author trailer, and resolver suppression use host configs

- preamble.ts: hostConfigDir derived from config.globalRoot instead of
  hardcoded Record
- utility.ts: generateCoAuthorTrailer reads from config.coAuthorTrailer
  instead of host switch statement
- gen-skill-docs.ts: suppressedResolvers from config skip resolver
  execution at placeholder replacement time (belt+suspenders with
  existing ctx.host checks in individual resolvers)

Golden-file comparison: all 3 hosts produce IDENTICAL output to baselines.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

scripts/gen-skill-docs.ts

@@ -437,10 +437,14 @@ function processTemplate(tmplPath: string, host: Host = 'claude'): { outputPath:
   const ctx: TemplateContext = { skillName, tmplPath, benefitsFrom, host, paths: HOST_PATHS[host], preambleTier };
 
   // Replace placeholders (supports parameterized: {{NAME:arg1:arg2}})
+  // Config-driven: suppressedResolvers return empty string for this host
+  const currentHostConfig = getHostConfig(host);
+  const suppressed = new Set(currentHostConfig.suppressedResolvers || []);
   let content = tmplContent.replace(/\{\{(\w+(?::[^}]+)?)\}\}/g, (match, fullKey) => {
     const parts = fullKey.split(':');
     const resolverName = parts[0];
     const args = parts.slice(1);
+    if (suppressed.has(resolverName)) return '';
     const resolver = RESOLVERS[resolverName];
     if (!resolver) throw new Error(`Unknown placeholder {{${resolverName}}} in ${relTmplPath}`);
     return args.length > 0 ? resolver(ctx, args) : resolver(ctx);

scripts/resolvers/preamble.ts

@@ -1,4 +1,5 @@
 import type { TemplateContext } from './types';
+import { getHostConfig } from '../../hosts/index';
 
 /**
  * Preamble architecture — why every skill needs this
@@ -13,10 +14,10 @@ import type { TemplateContext } from './types';
  */
 
 function generatePreambleBash(ctx: TemplateContext): string {
-  const hostConfigDir: Record<string, string> = { codex: '.codex', factory: '.factory' };
-  const runtimeRoot = (ctx.host !== 'claude')
+  const hostConfig = getHostConfig(ctx.host);
+  const runtimeRoot = hostConfig.usesEnvVars
     ? `_ROOT=$(git rev-parse --show-toplevel 2>/dev/null)
-GSTACK_ROOT="$HOME/${hostConfigDir[ctx.host]}/skills/gstack"
+GSTACK_ROOT="$HOME/${hostConfig.globalRoot}"
 [ -n "$_ROOT" ] && [ -d "$_ROOT/${ctx.paths.localSkillRoot}" ] && GSTACK_ROOT="$_ROOT/${ctx.paths.localSkillRoot}"
 GSTACK_BIN="$GSTACK_ROOT/bin"
 GSTACK_BROWSE="$GSTACK_ROOT/browse/dist"

scripts/resolvers/utility.ts

@@ -367,13 +367,9 @@ Minimum 0 per category.
 }
 
 export function generateCoAuthorTrailer(ctx: TemplateContext): string {
-  if (ctx.host === 'codex') {
-    return 'Co-Authored-By: OpenAI Codex <noreply@openai.com>';
-  }
-  if (ctx.host === 'factory') {
-    return 'Co-Authored-By: Factory Droid <droid@users.noreply.github.com>';
-  }
-  return 'Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>';
+  const { getHostConfig } = require('../../hosts/index');
+  const hostConfig = getHostConfig(ctx.host);
+  return hostConfig.coAuthorTrailer || 'Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>';
 }
 
 export function generateChangelogWorkflow(_ctx: TemplateContext): string {