feat(pages): add multi-language support for landing pages

Implement internationalization system for landing pages:
- Database model for storing language-specific translations
- Language configuration with default and enabled languages
- Language switcher in navigation across all templates
- Translation management UI in settings
- Support for 15 languages including English, Spanish, German, French, Japanese, Chinese
- Auto-detection and manual language selection
- AI-powered translation generation capability

services/pages/generate.go

@@ -7,6 +7,7 @@ import (
 	"context"
 	"errors"
 	"fmt"
+	"strconv"
 	"strings"
 
 	repo_model "code.gitcaddy.com/server/v3/models/repo"
@@ -34,8 +35,8 @@ type aiGeneratedConfig struct {
 		} `json:"secondary_cta"`
 	} `json:"hero"`
 	Stats      []pages_module.StatConfig      `json:"stats"`
-	ValueProps []pages_module.ValuePropConfig  `json:"value_props"`
-	Features   []pages_module.FeatureConfig    `json:"features"`
+	ValueProps []pages_module.ValuePropConfig `json:"value_props"`
+	Features   []pages_module.FeatureConfig   `json:"features"`
 	CTASection struct {
 		Headline    string `json:"headline"`
 		Subheadline string `json:"subheadline"`
@@ -66,9 +67,9 @@ func GenerateLandingPageContent(ctx context.Context, repo *repo_model.Repository
 			"repo_description": repo.Description,
 			"repo_url":         repoURL,
 			"topics":           topics,
-			"primary_language":  repo.PrimaryLanguage,
-			"stars":            fmt.Sprintf("%d", repo.NumStars),
-			"forks":            fmt.Sprintf("%d", repo.NumForks),
+			"primary_language": getPrimaryLanguageName(repo),
+			"stars":            strconv.Itoa(repo.NumStars),
+			"forks":            strconv.Itoa(repo.NumForks),
 			"readme":           truncateReadme(readme),
 			"instruction": `You are a landing page copywriter. Analyze this open-source repository and generate compelling landing page content.
 
@@ -165,6 +166,14 @@ Guidelines:
 	return config, nil
 }
 
+// getPrimaryLanguageName returns the primary language name for the repo, or empty string
+func getPrimaryLanguageName(repo *repo_model.Repository) string {
+	if repo.PrimaryLanguage != nil {
+		return repo.PrimaryLanguage.Language
+	}
+	return ""
+}
+
 // truncateReadme limits README content to avoid sending too much to the AI
 func truncateReadme(readme string) string {
 	const maxLen = 4000
@@ -173,3 +182,103 @@ func truncateReadme(readme string) string {
 	}
 	return readme[:maxLen] + "\n... (truncated)"
 }
+
+// TranslateLandingPageContent uses AI to translate landing page content to a target language.
+// Returns a JSON overlay string that can be deep-merged onto the base config.
+func TranslateLandingPageContent(ctx context.Context, repo *repo_model.Repository, config *pages_module.LandingConfig, targetLang string) (string, error) {
+	if !ai.IsEnabled() {
+		return "", errors.New("AI service is not enabled")
+	}
+
+	langNames := pages_module.LanguageDisplayNames()
+	langName := langNames[targetLang]
+	if langName == "" {
+		langName = targetLang
+	}
+
+	// Build the source content to translate
+	sourceContent := buildTranslatableContent(config)
+
+	client := ai.GetClient()
+	resp, err := client.ExecuteTask(ctx, &ai.ExecuteTaskRequest{
+		RepoID: repo.ID,
+		Task:   "landing_page_translate",
+		Context: map[string]string{
+			"target_language": langName,
+			"target_code":     targetLang,
+			"source_content":  sourceContent,
+			"instruction": `You are a professional translator. Translate the following landing page content to ` + langName + ` (` + targetLang + `).
+
+Return valid JSON as a partial config overlay. Only include the fields that have translatable text content.
+Do NOT translate URLs, brand names, or technical terms. Keep the same JSON structure.
+
+Return this exact JSON structure (only include fields with actual translated text):
+{
+  "hero": {
+    "headline": "translated headline",
+    "subheadline": "translated subheadline",
+    "primary_cta": {"label": "translated label"},
+    "secondary_cta": {"label": "translated label"}
+  },
+  "stats": [{"value": "keep original", "label": "translated label"}],
+  "value_props": [{"title": "translated", "description": "translated"}],
+  "features": [{"title": "translated", "description": "translated"}],
+  "cta_section": {
+    "headline": "translated",
+    "subheadline": "translated",
+    "button": {"label": "translated"}
+  },
+  "seo": {
+    "title": "translated",
+    "description": "translated"
+  }
+}
+
+Important:
+- Maintain the exact same number of items in arrays (stats, value_props, features)
+- Keep icon names, URLs, and image_urls unchanged
+- Use natural, marketing-quality translations (not literal/robotic)
+- Adapt idioms and expressions for the target culture`,
+		},
+	})
+	if err != nil {
+		return "", fmt.Errorf("AI translation failed: %w", err)
+	}
+
+	if !resp.Success {
+		return "", fmt.Errorf("AI translation error: %s", resp.Error)
+	}
+
+	// Validate it's valid JSON
+	var check map[string]any
+	if err := json.Unmarshal([]byte(resp.Result), &check); err != nil {
+		return "", fmt.Errorf("AI returned invalid JSON: %w", err)
+	}
+
+	return resp.Result, nil
+}
+
+// buildTranslatableContent extracts translatable text from a config for the AI
+func buildTranslatableContent(config *pages_module.LandingConfig) string {
+	data, _ := json.Marshal(map[string]any{
+		"hero": map[string]any{
+			"headline":      config.Hero.Headline,
+			"subheadline":   config.Hero.Subheadline,
+			"primary_cta":   map[string]string{"label": config.Hero.PrimaryCTA.Label},
+			"secondary_cta": map[string]string{"label": config.Hero.SecondaryCTA.Label},
+		},
+		"stats":       config.Stats,
+		"value_props": config.ValueProps,
+		"features":    config.Features,
+		"cta_section": map[string]any{
+			"headline":    config.CTASection.Headline,
+			"subheadline": config.CTASection.Subheadline,
+			"button":      map[string]string{"label": config.CTASection.Button.Label},
+		},
+		"seo": map[string]any{
+			"title":       config.SEO.Title,
+			"description": config.SEO.Description,
+		},
+	})
+	return string(data)
+}