docs(network): add the missing VAI-011 rationale doc

[jhumel-code]

What

Adds the missing docs/Policy/vercel_ai/network.md rationale doc for VAI-011 (Vercel AI tool HTTP call has no timeout) and regenerates the root + vercel POLICY_INDEX to include it.

Why

rules main and the released v0.1.3 engine both ship VAI-011 (it uses the has_http_call_without_timeout predicate added in schema 9), but the rulebook never carried its rationale doc — so check_rulebook failed on main with "rule VAI-011 has no rationale doc." This closes that gap. The doc is the one authored on the v9 network branch (cf/frosty-curie-e45239); its front-matter (high / 0.6 / tool, refs LLM10, LLM06) matches the rule exactly.

Verification

check_rulebook.py --strict and gen_index.py --check both pass against rules main (165 rules).

[jhumel-code]

Closing as a duplicate. PR #8 (cf/frosty-curie-e45239 -> main, MERGEABLE/CLEAN) already adds the VAI-011 rationale doc AND the OAI-016 structural retrofit + index updates — it is the complete rulebook side of the v9 network work. Merge #8 to close the VAI-011 documentation gap; this PR was a redundant subset I created before noticing #8 was open.