docs(policy): enforce server-side data ownership and backend LLM mediation

- clarify frontend may only rely on backend-issued session token cookie for auth

- forbid frontend browser storage for domain/business data

- require backend-mediated LLM calls across agent workflows

.github/agents/orchestrator.agent.md

@@ -159,6 +159,8 @@ Read the new version from `frontend/package.json` after bumping.
 - ALWAYS verify `git status` is clean before creating the branch.
 - ALWAYS use `gh pr create` (GitHub CLI) for pull requests — never instruct the user to open one manually unless `gh` is unavailable.
 - If `gh` is not installed, clearly tell the user and provide the exact PR title and body to paste into the GitHub UI.
+- ALWAYS enforce backend ownership of business/domain data; do not accept frontend browser storage solutions for domain persistence.
+- ALWAYS enforce backend-mediated LLM calls; frontend must never call LLM providers directly.
 
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