feat: add provider and model routing tables, admin UI, and audit category for gateway

Implement the multi-provider routing system for the OpenAI gateway, including two new database tables (`gateway_providers`, `gateway_models`) ensured at init, a new admin page at `/admin/gateway` with full CRUD for providers and model routes, and a `"gateway"` audit category mapped to `"ai"`. The routing layer sits transparently on top of the existing single-provider default path: unmatched model names fall through unchanged, while matched routes forward to the configured provider with their own pricing economy, vision model, and context window. Cross-worker cache invalidation uses a shared `_ROUTING_CACHE` bumped via `"gateway_routing"` cache version.

devplacepy/services/devii/actions/catalog.py

@@ -1696,6 +1696,102 @@ ACTIONS: tuple[Action, ...] = (
         ),
         requires_admin=True,
     ),
+    Action(
+        name="gateway_providers",
+        method="GET",
+        path="/admin/gateway/providers",
+        summary="List OpenAI gateway providers (admin only)",
+        description=(
+            "Returns JSON: the named upstream providers used by model routes, plus the implicit "
+            "'default' provider read from the gateway service config."
+        ),
+        handler="http",
+        requires_admin=True,
+        read_only=True,
+    ),
+    Action(
+        name="gateway_provider_set",
+        method="POST",
+        path="/admin/gateway/providers",
+        summary="Create or update a gateway provider (admin only)",
+        description=(
+            "Adds or updates a named upstream provider. base_url is the OpenAI-compatible "
+            "chat-completions endpoint; the embeddings endpoint is derived from it."
+        ),
+        handler="http",
+        requires_admin=True,
+        params=(
+            body("name", "Provider name (letters, numbers, hyphen, underscore).", required=True),
+            body("base_url", "Chat-completions endpoint URL."),
+            body("api_key", "Upstream API key."),
+            Param(
+                name="is_active",
+                location="body",
+                description="Whether the provider is active ('1' or '0').",
+                required=False,
+                type="boolean",
+            ),
+        ),
+    ),
+    Action(
+        name="gateway_provider_delete",
+        method="DELETE",
+        path="/admin/gateway/providers/{name}",
+        summary="Delete a gateway provider (admin only, confirmation required)",
+        handler="http",
+        requires_admin=True,
+        params=(path("name", "Provider name."), confirm()),
+    ),
+    Action(
+        name="gateway_models",
+        method="GET",
+        path="/admin/gateway/models",
+        summary="List OpenAI gateway model routes (admin only)",
+        description=(
+            "Returns JSON: every source-model route with its provider, target model, kind "
+            "(chat/embed), optional vision model, context window, and per-model pricing economy."
+        ),
+        handler="http",
+        requires_admin=True,
+        read_only=True,
+    ),
+    Action(
+        name="gateway_model_set",
+        method="POST",
+        path="/admin/gateway/models",
+        summary="Create or update a gateway model route (admin only)",
+        description=(
+            "Maps a requested source_model onto a provider + target_model, each with its own "
+            "pricing. kind is 'chat' or 'embed'. A vision_model adds image-to-text augmentation "
+            "for chat routes. Prices are USD per 1,000,000 tokens; chat uses cache-hit/cache-miss/"
+            "output, embeddings use input, vision uses input/output."
+        ),
+        handler="http",
+        requires_admin=True,
+        params=(
+            body("source_model", "Model name clients request.", required=True),
+            body("provider", "Provider name, or blank for the default upstream."),
+            body("target_model", "Model name sent upstream.", required=True),
+            body("kind", "Route kind: 'chat' or 'embed'."),
+            body("vision_provider", "Provider for image description, or blank for the route provider."),
+            body("vision_model", "Vision model name (blank disables the merge)."),
+            Param(name="context_window", location="body", description="Max context tokens (0 = unknown).", required=False, type="integer"),
+            Param(name="price_cache_hit_per_m", location="body", description="USD per 1M cache-hit input tokens.", required=False, type="number"),
+            Param(name="price_cache_miss_per_m", location="body", description="USD per 1M cache-miss input tokens.", required=False, type="number"),
+            Param(name="price_output_per_m", location="body", description="USD per 1M output tokens.", required=False, type="number"),
+            Param(name="price_input_per_m", location="body", description="USD per 1M input tokens (embed/vision).", required=False, type="number"),
+            Param(name="is_active", location="body", description="Whether the route is active ('1' or '0').", required=False, type="boolean"),
+        ),
+    ),
+    Action(
+        name="gateway_model_delete",
+        method="DELETE",
+        path="/admin/gateway/models/{source_model}",
+        summary="Delete a gateway model route (admin only, confirmation required)",
+        handler="http",
+        requires_admin=True,
+        params=(path("source_model", "Source model name."), confirm()),
+    ),
 )
 
 PLATFORM_CATALOG = Catalog(actions=ACTIONS)

devplacepy/services/devii/actions/dispatcher.py

@@ -56,6 +56,8 @@ CONFIRM_REQUIRED = {
     "db_insert_row",
     "db_update_row",
     "db_delete_row",
+    "gateway_provider_delete",
+    "gateway_model_delete",
 }
 
 CONDITIONAL_CONFIRM = {