Grounding pipeline and recipe-search settings API

recipes.Grounder ties search, fetch/extract, Rank, the photo cache and
normalize_recipe together. Ground(ctx, dishName, query) reuses a stored
source_url among the top candidates without fetching, otherwise tries the
ranked recipes best first and stores the photo, recipe, ingredients and
steps in one transaction, returning Grounded{recipe_id, photo_id, method,
minutes_total, difficulty, source_url, site_name} or a typed
*ErrUngroundable listing every reason. GroundURL grounds a pasted URL the
same way; GroundMany grounds items 3 at a time with per-item results.

PhotoCache is split into DownloadPhoto (fetch, decode, size check, no
writes) and CachePhoto(ctx, tx, photo), which records the row in the
caller's transaction; RemovePhotoFiles cleans up after a rollback.

Migration 0007 adds photo_id, method, difficulty and minutes_total to
recipes, and api_key_last4 to recipe_search_settings. SearXNG is now
called at recipe_search_settings.base_url.

GET/PATCH /api/v1/settings/recipe-search (Brave key sealed with
secretbox, only api_key_set and api_key_last4 returned) and POST
/api/v1/settings/recipe-search/test (searches "chicken tikka masala",
returns the count, 409 not_configured or 502 search_failed).

Maestro task 53afd59c-6c35-4af7-904c-6c167d1ad69d.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

internal/recipes/search_test.go

@@ -3,6 +3,7 @@ package recipes
 import (
 	"context"
 	"crypto/rand"
+	"database/sql"
 	"encoding/base64"
 	"errors"
 	"net/http"
@@ -262,7 +263,7 @@ func TestNewSearchProvider(t *testing.T) {
 		t.Fatal(err)
 	}
 
-	p, err := NewSearchProvider(db.RecipeSearchSetting{Provider: "brave", ApiKeyCt: ct}, box, "")
+	p, err := NewSearchProvider(db.RecipeSearchSetting{Provider: "brave", ApiKeyCt: ct}, box)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -270,7 +271,7 @@ func TestNewSearchProvider(t *testing.T) {
 		t.Errorf("provider = %#v, want Brave with decrypted key", p)
 	}
 
-	p, err = NewSearchProvider(db.RecipeSearchSetting{Provider: "searxng"}, box, "http://searxng:8080")
+	p, err = NewSearchProvider(db.RecipeSearchSetting{Provider: "searxng", BaseUrl: sql.NullString{String: "http://searxng:8080", Valid: true}}, box)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -278,16 +279,13 @@ func TestNewSearchProvider(t *testing.T) {
 		t.Errorf("provider = %#v, want SearXNG at http://searxng:8080/search", p)
 	}
 
-	for name, tc := range map[string]struct {
-		s   db.RecipeSearchSetting
-		url string
-	}{
-		"brave without key":   {db.RecipeSearchSetting{Provider: "brave"}, ""},
-		"brave bad key":       {db.RecipeSearchSetting{Provider: "brave", ApiKeyCt: []byte("not a token at all, far too plain")}, ""},
-		"searxng without URL": {db.RecipeSearchSetting{Provider: "searxng"}, ""},
-		"unknown provider":    {db.RecipeSearchSetting{Provider: "google"}, ""},
+	for name, s := range map[string]db.RecipeSearchSetting{
+		"brave without key":   {Provider: "brave"},
+		"brave bad key":       {Provider: "brave", ApiKeyCt: []byte("not a token at all, far too plain")},
+		"searxng without URL": {Provider: "searxng"},
+		"unknown provider":    {Provider: "google"},
 	} {
-		if _, err := NewSearchProvider(tc.s, box, tc.url); err == nil {
+		if _, err := NewSearchProvider(s, box); err == nil {
 			t.Errorf("%s: succeeded, want error", name)
 		}
 	}