feat: add AI Bridge request logs model filter (#22230)

This pull-request implements a simple filtering logic so that we're able
to pick which model the user actually used when logs were sent to AI
Bridge.

- Add `GET /aibridge/models` API endpoint that returns distinct model
names from AI Bridge interceptions, with pagination and search support
- New `ListAIBridgeModels` SQL query using case-sensitive prefix
matching (`LIKE model || '%'`) to allow B-tree index usage
- Hand-written `ListAuthorizedAIBridgeModels` in `modelqueries.go` for
RBAC authorization filter injection
- `AIBridgeModels` search query parser in searchquery/search.go
(defaults bare terms to the `model` field)
- dbauthz wrappers, dbmetrics, and dbmock implementations for the new
query

<img width="292" height="185" alt="image"
src="https://github.com/user-attachments/assets/134771df-2d26-4c54-acc4-27f58128b351"
/>

enterprise/coderd/aibridge.go

@@ -22,7 +22,9 @@ import (
 
 const (
 	maxListInterceptionsLimit     = 1000
+	maxListModelsLimit            = 1000
 	defaultListInterceptionsLimit = 100
+	defaultListModelsLimit        = 100
 	// aiBridgeRateLimitWindow is the fixed duration for rate limiting AI Bridge
 	// requests. This is hardcoded to keep configuration simple.
 	aiBridgeRateLimitWindow = time.Second
@@ -41,6 +43,7 @@ func aibridgeHandler(api *API, middlewares ...func(http.Handler) http.Handler) f
 		r.Group(func(r chi.Router) {
 			r.Use(middlewares...)
 			r.Get("/interceptions", api.aiBridgeListInterceptions)
+			r.Get("/models", api.aiBridgeListModels)
 		})
 
 		// Apply overload protection middleware to the aibridged handler.
@@ -173,6 +176,58 @@ func (api *API) aiBridgeListInterceptions(rw http.ResponseWriter, r *http.Reques
 	})
 }
 
+// aiBridgeListModels returns all AI Bridge models a user can see.
+//
+// @Summary List AI Bridge models
+// @ID list-ai-bridge-models
+// @Security CoderSessionToken
+// @Produce json
+// @Tags AI Bridge
+// @Success 200 {array} string
+// @Router /aibridge/models [get]
+func (api *API) aiBridgeListModels(rw http.ResponseWriter, r *http.Request) {
+	ctx := r.Context()
+
+	page, ok := coderd.ParsePagination(rw, r)
+	if !ok {
+		return
+	}
+
+	if page.Limit == 0 {
+		page.Limit = defaultListModelsLimit
+	}
+
+	if page.Limit > maxListModelsLimit || page.Limit < 1 {
+		httpapi.Write(ctx, rw, http.StatusBadRequest, codersdk.Response{
+			Message: "Invalid pagination limit value.",
+			Detail:  fmt.Sprintf("Pagination limit must be in range (0, %d]", maxListModelsLimit),
+		})
+		return
+	}
+
+	queryStr := r.URL.Query().Get("q")
+	filter, errs := searchquery.AIBridgeModels(queryStr, page)
+
+	if len(errs) > 0 {
+		httpapi.Write(ctx, rw, http.StatusBadRequest, codersdk.Response{
+			Message:     "Invalid AI Bridge models search query.",
+			Validations: errs,
+		})
+		return
+	}
+
+	models, err := api.Database.ListAIBridgeModels(ctx, filter)
+	if err != nil {
+		httpapi.Write(ctx, rw, http.StatusInternalServerError, codersdk.Response{
+			Message: "Internal error getting AI Bridge models.",
+			Detail:  err.Error(),
+		})
+		return
+	}
+
+	httpapi.Write(ctx, rw, http.StatusOK, models)
+}
+
 func populatedAndConvertAIBridgeInterceptions(ctx context.Context, db database.Store, dbInterceptions []database.ListAIBridgeInterceptionsRow) ([]codersdk.AIBridgeInterception, error) {
 	ids := make([]uuid.UUID, len(dbInterceptions))
 	for i, row := range dbInterceptions {