feat: implement section-based homepage management system

Add structured JSON sections to ContentPage for multi-language homepage editing:

Database:
- Add `sections` JSON column to content_pages table
- Migration z8i9j0k1l2m3 adds the column

Schema:
- New models/schema/homepage_sections.py with Pydantic schemas
- TranslatableText for language-keyed translations
- HeroSection, FeaturesSection, PricingSection, CTASection

Templates:
- New section partials in app/templates/platform/sections/
- Updated homepage-default.html to render sections dynamically
- Fallback to placeholder content when sections not configured

Service:
- update_homepage_sections() - validate and save all sections
- update_single_section() - update individual section
- get_default_sections() - empty structure for new homepages

API:
- GET /{page_id}/sections - get sections with platform languages
- PUT /{page_id}/sections - update all sections
- PUT /{page_id}/sections/{section_name} - update single section

Admin UI:
- Section editor appears when editing homepage (slug='home')
- Language tabs from platform.supported_languages
- Accordion sections for Hero, Features, Pricing, CTA
- Button/feature card repeaters with add/remove

Also fixes broken line 181 in z4e5f6a7b8c9 migration.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

models/database/content_page.py

@@ -29,6 +29,7 @@ Features:
 from datetime import UTC, datetime
 
 from sqlalchemy import (
+    JSON,
     Boolean,
     Column,
     DateTime,
@@ -107,6 +108,16 @@ class ContentPage(Base):
     # Only used for landing pages (slug='landing' or 'home')
     template = Column(String(50), default="default", nullable=False)
 
+    # Homepage sections (structured JSON for section-based editing)
+    # Only used for homepage (slug='home'). Contains hero, features, pricing, cta sections
+    # with multi-language support via TranslatableText pattern
+    sections = Column(
+        JSON,
+        nullable=True,
+        default=None,
+        comment="Structured homepage sections (hero, features, pricing, cta) with i18n",
+    )
+
     # SEO
     meta_description = Column(String(300), nullable=True)
     meta_keywords = Column(String(300), nullable=True)
@@ -199,6 +210,7 @@ class ContentPage(Base):
             "content": self.content,
             "content_format": self.content_format,
             "template": self.template,
+            "sections": self.sections,
             "meta_description": self.meta_description,
             "meta_keywords": self.meta_keywords,
             "is_published": self.is_published,

models/schema/homepage_sections.py

@@ -0,0 +1,174 @@
+"""
+Homepage Section Schemas with Dynamic Multi-Language Support.
+
+Language codes are NOT hardcoded - they come from platform.supported_languages.
+The TranslatableText class stores translations as a dict where keys are language codes.
+
+Example JSON structure:
+{
+    "hero": {
+        "enabled": true,
+        "title": {"translations": {"fr": "Bienvenue", "en": "Welcome"}},
+        "subtitle": {"translations": {...}},
+        "buttons": [...]
+    },
+    "features": {...},
+    "pricing": {...},
+    "cta": {...}
+}
+"""
+
+from pydantic import BaseModel, Field
+from typing import Optional
+
+
+class TranslatableText(BaseModel):
+    """
+    Text field with translations stored as language-keyed dict.
+
+    Languages come from platform.supported_languages (not hardcoded).
+    Use .get(lang, default_lang) to retrieve translation with fallback.
+    """
+
+    translations: dict[str, str] = Field(
+        default_factory=dict, description="Language code -> translated text mapping"
+    )
+
+    def get(self, lang: str, default_lang: str = "fr") -> str:
+        """Get translation with fallback to default language."""
+        return self.translations.get(lang) or self.translations.get(default_lang) or ""
+
+    def set(self, lang: str, text: str) -> None:
+        """Set translation for a language."""
+        self.translations[lang] = text
+
+    def has_translation(self, lang: str) -> bool:
+        """Check if translation exists for language."""
+        return bool(self.translations.get(lang))
+
+
+class HeroButton(BaseModel):
+    """Button in hero or CTA section."""
+
+    text: TranslatableText = Field(default_factory=TranslatableText)
+    url: str = ""
+    style: str = Field(default="primary", description="primary, secondary, outline")
+
+
+class HeroSection(BaseModel):
+    """Hero section configuration."""
+
+    enabled: bool = True
+    badge_text: Optional[TranslatableText] = None
+    title: TranslatableText = Field(default_factory=TranslatableText)
+    subtitle: TranslatableText = Field(default_factory=TranslatableText)
+    background_type: str = Field(
+        default="gradient", description="gradient, image, solid"
+    )
+    background_image: Optional[str] = None
+    buttons: list[HeroButton] = Field(default_factory=list)
+
+
+class FeatureCard(BaseModel):
+    """Single feature in features section."""
+
+    icon: str = ""
+    title: TranslatableText = Field(default_factory=TranslatableText)
+    description: TranslatableText = Field(default_factory=TranslatableText)
+
+
+class FeaturesSection(BaseModel):
+    """Features section configuration."""
+
+    enabled: bool = True
+    title: TranslatableText = Field(default_factory=TranslatableText)
+    subtitle: Optional[TranslatableText] = None
+    features: list[FeatureCard] = Field(default_factory=list)
+    layout: str = Field(default="grid", description="grid, list, cards")
+
+
+class PricingSection(BaseModel):
+    """Pricing section configuration."""
+
+    enabled: bool = True
+    title: TranslatableText = Field(default_factory=TranslatableText)
+    subtitle: Optional[TranslatableText] = None
+    use_subscription_tiers: bool = Field(
+        default=True, description="Pull pricing from subscription_tiers table dynamically"
+    )
+
+
+class CTASection(BaseModel):
+    """Call-to-action section configuration."""
+
+    enabled: bool = True
+    title: TranslatableText = Field(default_factory=TranslatableText)
+    subtitle: Optional[TranslatableText] = None
+    buttons: list[HeroButton] = Field(default_factory=list)
+    background_type: str = Field(
+        default="gradient", description="gradient, image, solid"
+    )
+
+
+class HomepageSections(BaseModel):
+    """Complete homepage sections structure."""
+
+    hero: Optional[HeroSection] = None
+    features: Optional[FeaturesSection] = None
+    pricing: Optional[PricingSection] = None
+    cta: Optional[CTASection] = None
+
+    @classmethod
+    def get_empty_structure(cls, languages: list[str]) -> "HomepageSections":
+        """
+        Create empty section structure with language placeholders.
+
+        Args:
+            languages: List of language codes from platform.supported_languages
+
+        Returns:
+            HomepageSections with empty translations for all languages
+        """
+
+        def make_translatable(langs: list[str]) -> TranslatableText:
+            return TranslatableText(translations={lang: "" for lang in langs})
+
+        return cls(
+            hero=HeroSection(
+                title=make_translatable(languages),
+                subtitle=make_translatable(languages),
+                buttons=[],
+            ),
+            features=FeaturesSection(
+                title=make_translatable(languages),
+                features=[],
+            ),
+            pricing=PricingSection(
+                title=make_translatable(languages),
+                use_subscription_tiers=True,
+            ),
+            cta=CTASection(
+                title=make_translatable(languages),
+                buttons=[],
+            ),
+        )
+
+
+# =============================================================================
+# API Request/Response Schemas
+# =============================================================================
+
+
+class SectionUpdateRequest(BaseModel):
+    """Request to update a single section."""
+
+    section_name: str = Field(..., description="hero, features, pricing, or cta")
+    section_data: dict = Field(..., description="Section configuration")
+
+
+class HomepageSectionsResponse(BaseModel):
+    """Response containing all homepage sections with platform language info."""
+
+    sections: Optional[HomepageSections] = None
+    supported_languages: list[str] = Field(default_factory=lambda: ["fr", "de", "en"])
+    default_language: str = "fr"