chore: enforce kickoff clarifications gate in story rule

Require clarification questions before plan updates/commits, require AskQuestion for blocking decisions, and mandate a Kickoff clarifications section in plan docs.

.cursor/rules/story-kickoff.md

@@ -13,6 +13,13 @@ When the user starts work on a **Linear issue** (e.g. issue key `NEO-5`, phrases
 - Use **concrete questions**, often with short options when helpful; group related questions so the user can answer in one pass.
 - When the Cursor session supports it (**Agent** mode), prefer **`AskQuestion`** multiple-choice for blocking decisions (same pattern as [story-end](story-end.md) §4a for **Linear state** after “end story”) instead of only long prose lists.
 
+### Clarifications gate (hard requirement)
+
+- **Do not** create or update `docs/plans/{KEY}-implementation-plan.md` until clarification questions have been asked and the user has answered (or explicitly says no questions are needed).
+- If at least one **blocking decision** exists in planning, use **`AskQuestion`** (Agent mode) instead of prose-only questions.
+- If kickoff has zero questions, explicitly record why in the plan under a **Kickoff clarifications** section with evidence from Linear + repo context.
+- **Do not commit** a kickoff plan until the clarification step above is complete.
+
 ## 1. Load Linear context
 
 - Fetch the issue when possible (Linear MCP `get_issue` / `list_issues`, server **`plugin-linear-linear`**), or use a URL / pasted description the user provides.
@@ -48,6 +55,7 @@ When the user starts work on a **Linear issue** (e.g. issue key `NEO-5`, phrases
 **Required sections** in that file (do **not** ship a plan that omits any of these):
 
 - Story reference (key, title, link if available)
+- Kickoff clarifications (questions asked + answers, or explicit “No clarifications needed” with reason)
 - Goal, scope, and out-of-scope (from Linear)
 - Acceptance criteria checklist (from Linear)
 - Technical approach (concise)