fix(short_story): remove requires block, infer genre/audience/style from task description

Templates spawned from genesis only receive a description, not pre-set
context variables. Removing requires: prevents step-0 failures when the
story brief is rich enough for Iris to infer genre/audience/prose style.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

templates/short_story.yml

@@ -7,11 +7,6 @@ agent_prompt:
   - "= identity.md"
   - "agent.rag.json"
 
-requires:
-  - genre_name
-  - genre_audience
-  - prose_style
-
 sections:
   - agent
   - project
@@ -29,6 +24,7 @@ steps:
 
       GENRE: {genre_name}  |  AUDIENCE: {genre_audience}
       PROSE STYLE: {prose_style}
+      (If any of the above are empty, infer genre, audience, and prose style from the task description and project goal.)
       TARGET LENGTH: 3,000–15,000 words (short story to novelette)
 
       Before writing, plan the story: