feat(workflow): add preparer role as first step in solve-issue workflow

- New package: @uncaged/workflow-role-preparer with PreparerMeta type,
  schema, system prompt, and extract prompt
- Preparer locates/clones repo, detects toolchain and conventions
- Moderator updated: preparer → planner → coder → reviewer → committer
- solve-issue template re-exports preparer types
- Tests updated for new flow (129 pass, 0 fail)

Fixes #28

packages/workflow-template-solve-issue/src/moderator.ts

@@ -48,11 +48,15 @@ export const solveIssueModerator: Moderator<SolveIssueMeta> = (ctx) => {
   const maxRounds = ctx.start.meta.maxRounds;
 
   if (ctx.steps.length === 0) {
-    return "planner";
+    return "preparer";
   }
 
   const last = ctx.steps[ctx.steps.length - 1];
 
+  if (last.role === "preparer") {
+    return "planner";
+  }
+
   if (last.role === "planner") {
     return "coder";
   }