fix(showcase): call ctx.log.info/.warn in hook bodies — sandbox ctx.log is an object

AuditTaskCompletion and WarnOverBudget guarded their log line with
`if (typeof ctx.log === 'function')`, but the sandboxed hook runtime installs
`ctx.log` as an object `{ info, warn, error }` (quickjs-runner installCtx /
ScriptContext.log), so the guard was always false and the lines were dead code.
Call the correct object-method API: `ctx.log.info(...)` for the audit hook and
`ctx.log.warn(...)` for the over-budget warning. Both already declare
capabilities: ['log'], so no capability change is needed.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Author: os-zhuang

examples/app-showcase/src/data/hooks/index.ts

@@ -47,7 +47,7 @@ export const AuditTaskCompletionHook = {
   condition: "record.done == true",
   body: {
     language: 'js' as const,
-    source: "var r = ctx.result || ctx.input || {}; if (typeof ctx.log === 'function') ctx.log('task completed: ' + (r.title || r.id || 'unknown'));",
+    source: "var r = ctx.result || ctx.input || {}; ctx.log.info('task completed: ' + (r.title || r.id || 'unknown'));",
     capabilities: ['log'] as ('log')[],
   },
   async: true,
@@ -70,7 +70,7 @@ export const WarnOverBudgetHook = {
   condition: "has(record.spent) && has(record.budget) && record.spent > record.budget",
   body: {
     language: 'js' as const,
-    source: "var r = ctx.result || ctx.input || {}; if (typeof ctx.log === 'function') ctx.log('project over budget: ' + (r.name || r.id || 'unknown') + ' (' + r.spent + ' / ' + r.budget + ')');",
+    source: "var r = ctx.result || ctx.input || {}; ctx.log.warn('project over budget: ' + (r.name || r.id || 'unknown') + ' (' + r.spent + ' / ' + r.budget + ')');",
     capabilities: ['log'] as ('log')[],
   },
   async: true,