refactor: rename public routes and templates to platform

Complete the public -> platform naming migration across the codebase.
This aligns with the naming convention where "platform" refers to
the marketing/public-facing pages of the platform itself.

Changes:
- Update all imports from public to platform modules
- Update template references from public/ to platform/
- Update route registrations to use platform prefix
- Update documentation to reflect new naming
- Update test files for platform API endpoints

Files affected:
- app/api/main.py - router imports
- app/modules/*/routes/*/platform.py - route definitions
- app/modules/*/templates/*/platform/ - template files
- app/modules/routes.py - route discovery
- docs/* - documentation updates
- tests/integration/api/v1/platform/ - test files

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

app/modules/billing/templates/billing/platform/pricing.html

@@ -1,6 +1,6 @@
 {# app/templates/platform/pricing.html #}
 {# Standalone Pricing Page #}
-{% extends "public/base.html" %}
+{% extends "platform/base.html" %}
 
 {% block title %}{{ _("cms.platform.pricing.title") }} - Wizamart{% endblock %}
 

app/modules/billing/templates/billing/platform/signup-success.html

@@ -1,6 +1,6 @@
 {# app/templates/platform/signup-success.html #}
 {# Signup Success Page #}
-{% extends "public/base.html" %}
+{% extends "platform/base.html" %}
 
 {% block title %}{{ _("cms.platform.success.title") }}{% endblock %}
 

app/modules/billing/templates/billing/platform/signup.html

@@ -1,6 +1,6 @@
 {# app/templates/platform/signup.html #}
 {# Multi-step Signup Wizard #}
-{% extends "public/base.html" %}
+{% extends "platform/base.html" %}
 
 {% block title %}Start Your Free Trial - Wizamart{% endblock %}
 
@@ -321,7 +321,7 @@ function signupWizard() {
         async startSignup() {
             this.loading = true;
             try {
-                const response = await fetch('/api/v1/public/signup/start', {
+                const response = await fetch('/api/v1/platform/signup/start', {
                     method: 'POST',
                     headers: { 'Content-Type': 'application/json' },
                     body: JSON.stringify({
@@ -352,7 +352,7 @@ function signupWizard() {
 
                 try {
                     // First lookup the vendor
-                    const lookupResponse = await fetch('/api/v1/public/letzshop-vendors/lookup', {
+                    const lookupResponse = await fetch('/api/v1/platform/letzshop-vendors/lookup', {
                         method: 'POST',
                         headers: { 'Content-Type': 'application/json' },
                         body: JSON.stringify({ url: this.letzshopUrl })
@@ -364,7 +364,7 @@ function signupWizard() {
                         this.letzshopVendor = lookupData.vendor;
 
                         // Claim the vendor
-                        const claimResponse = await fetch('/api/v1/public/signup/claim-vendor', {
+                        const claimResponse = await fetch('/api/v1/platform/signup/claim-vendor', {
                             method: 'POST',
                             headers: { 'Content-Type': 'application/json' },
                             body: JSON.stringify({
@@ -411,7 +411,7 @@ function signupWizard() {
             this.accountError = null;
 
             try {
-                const response = await fetch('/api/v1/public/signup/create-account', {
+                const response = await fetch('/api/v1/platform/signup/create-account', {
                     method: 'POST',
                     headers: { 'Content-Type': 'application/json' },
                     body: JSON.stringify({
@@ -461,7 +461,7 @@ function signupWizard() {
 
             // Get SetupIntent
             try {
-                const response = await fetch('/api/v1/public/signup/setup-payment', {
+                const response = await fetch('/api/v1/platform/signup/setup-payment', {
                     method: 'POST',
                     headers: { 'Content-Type': 'application/json' },
                     body: JSON.stringify({ session_id: this.sessionId })
@@ -500,7 +500,7 @@ function signupWizard() {
                 }
 
                 // Complete signup
-                const response = await fetch('/api/v1/public/signup/complete', {
+                const response = await fetch('/api/v1/platform/signup/complete', {
                     method: 'POST',
                     headers: { 'Content-Type': 'application/json' },
                     body: JSON.stringify({