Per-tree AI model policy (owner-only admin view)

The operator decides which model providers exist (env / registry — Anthropic,
OpenAI, x.AI, Ollama, several at once). The *tree owner* decides who uses which:

- Members' assistant -> one configured provider (or none)
- Recommender (association/connection finder) -> one configured provider (or none)
- Owner -> may use any configured provider

Backend: two nullable columns on `trees` (ai_member_provider,
ai_recommender_provider) + migration; `configured_llm_providers()` exposes the
registry as {name, model} with no secrets; owner-gated GET/PATCH
/trees/{id}/ai validate names against the configured set. Frontend: owner-only
"AI models" page with a dropdown per role, graceful 403 for non-owners, and a
sidebar link.

Per-model-within-a-provider selection is a follow-up; today each provider maps
to its single configured model.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Signed-off-by: Justin Paul <justin@jpaul.me>

frontend/lib/api/schema.d.ts

@@ -1031,6 +1031,24 @@ export interface paths {
         patch?: never;
         trace?: never;
     };
+    "/api/v1/trees/{tree_id}/ai": {
+        parameters: {
+            query?: never;
+            header?: never;
+            path?: never;
+            cookie?: never;
+        };
+        /** Get Ai Policy */
+        get: operations["get_ai_policy_api_v1_trees__tree_id__ai_get"];
+        put?: never;
+        post?: never;
+        delete?: never;
+        options?: never;
+        head?: never;
+        /** Update Ai Policy */
+        patch: operations["update_ai_policy_api_v1_trees__tree_id__ai_patch"];
+        trace?: never;
+    };
 }
 export type webhooks = Record<string, never>;
 export interface components {
@@ -1215,6 +1233,13 @@ export interface components {
             /** Updated */
             updated: number;
         };
+        /** ConfiguredProvider */
+        ConfiguredProvider: {
+            /** Name */
+            name: string;
+            /** Model */
+            model: string;
+        };
         /** DeceasedApply */
         DeceasedApply: {
             /** Person Ids */
@@ -1886,6 +1911,24 @@ export interface components {
             /** Token */
             token: string;
         };
+        /** TreeAiPolicyRead */
+        TreeAiPolicyRead: {
+            /** Member Provider */
+            member_provider: string | null;
+            /** Recommender Provider */
+            recommender_provider: string | null;
+            /** Configured Providers */
+            configured_providers: components["schemas"]["ConfiguredProvider"][];
+            /** Default Provider */
+            default_provider: string;
+        };
+        /** TreeAiPolicyUpdate */
+        TreeAiPolicyUpdate: {
+            /** Member Provider */
+            member_provider?: string | null;
+            /** Recommender Provider */
+            recommender_provider?: string | null;
+        };
         /** TreeCreate */
         TreeCreate: {
             /** Name */
@@ -4651,4 +4694,70 @@ export interface operations {
             };
         };
     };
+    get_ai_policy_api_v1_trees__tree_id__ai_get: {
+        parameters: {
+            query?: never;
+            header?: never;
+            path: {
+                tree_id: string;
+            };
+            cookie?: never;
+        };
+        requestBody?: never;
+        responses: {
+            /** @description Successful Response */
+            200: {
+                headers: {
+                    [name: string]: unknown;
+                };
+                content: {
+                    "application/json": components["schemas"]["TreeAiPolicyRead"];
+                };
+            };
+            /** @description Validation Error */
+            422: {
+                headers: {
+                    [name: string]: unknown;
+                };
+                content: {
+                    "application/json": components["schemas"]["HTTPValidationError"];
+                };
+            };
+        };
+    };
+    update_ai_policy_api_v1_trees__tree_id__ai_patch: {
+        parameters: {
+            query?: never;
+            header?: never;
+            path: {
+                tree_id: string;
+            };
+            cookie?: never;
+        };
+        requestBody: {
+            content: {
+                "application/json": components["schemas"]["TreeAiPolicyUpdate"];
+            };
+        };
+        responses: {
+            /** @description Successful Response */
+            200: {
+                headers: {
+                    [name: string]: unknown;
+                };
+                content: {
+                    "application/json": components["schemas"]["TreeAiPolicyRead"];
+                };
+            };
+            /** @description Validation Error */
+            422: {
+                headers: {
+                    [name: string]: unknown;
+                };
+                content: {
+                    "application/json": components["schemas"]["HTTPValidationError"];
+                };
+            };
+        };
+    };
 }