fix: initialize options.hooks before merging YAML node hooks (#1177)

When a workflow node defines hooks (PreToolUse/PostToolUse) in YAML but
no hooks exist yet on the options object, applyNodeConfig crashes with
"undefined is not an object" because it tries to assign properties on
the undefined options.hooks.

Initialize options.hooks to {} before the merge loop.

Reproduces with: archon workflow run archon-architect (which uses
per-node hooks extensively).

Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

packages/providers/src/claude/provider.ts

@@ -382,6 +382,9 @@ async function applyNodeConfig(
     if (Object.keys(builtHooks).length > 0) {
       // Merge with existing hooks (PostToolUse capture hook)
       const existingHooks = options.hooks as SDKHooksMap | undefined;
+      if (!options.hooks) {
+        (options as Record<string, unknown>).hooks = {};
+      }
       for (const [event, matchers] of Object.entries(builtHooks)) {
         if (!matchers) continue;
         const existing = existingHooks?.[event] as HookCallbackMatcher[] | undefined;