Feat/space cta optimization (#2089)

* feat(wizard): persist wizard progress to backend for session resumption

Store wizard step, selected adapter, created bot UUID, and runner
selection in the metadata table. On revisit, the wizard restores
progress and verifies the bot still exists. Progress is cleared
automatically when the wizard is completed or skipped.

* feat(dynamic-form): optimize LLM model selection with space login CTA and improve localization strings

* feat(web): add LangBot Cloud CTA for webhook URL fields in community edition

Show a subtle hint below webhook URL fields prompting users about
LangBot Cloud's public endpoint, only visible in community edition.
Covers all 8 webhook-based adapters with i18n support (4 locales).

web/src/i18n/locales/en-US.ts

@@ -231,6 +231,10 @@ const enUS = {
     loginWithSpace: 'Login with Space',
     loginToUseModels: 'Login with Space to use cloud models',
     noModels: 'No models configured',
+    langbotModels: 'LangBot Models',
+    spaceTrialTooltip:
+      'Free trial credits available! Login with Space to access cloud models with zero configuration.',
+    unlockModels: 'Login to use',
     editProvider: 'Edit Provider',
     addProvider: 'Add Provider',
     addProviderHint: 'Add providers to use models from other sources',
@@ -314,6 +318,9 @@ const enUS = {
       'Click the input to select all, then press Ctrl+C (Mac: Cmd+C) to copy, or click the button',
     webhookUrlHintEither:
       'Use either of the two URLs above in your platform configuration',
+    webhookSaasHint:
+      'Webhook requires a publicly accessible domain. LangBot Cloud provides a ready-to-use public endpoint for your bot.',
+    webhookSaasLink: 'Learn more about LangBot Cloud',
     logLevel: 'Log Level',
     allLevels: 'All Levels',
     selectLevel: 'Select Level',