feat: add React Joyride onboarding tour for new users (#870) (#872)

Implement guided onboarding tour that auto-starts for first-time users
and can be replayed via a Help (?) button in the nav bar.

- Add onboarding_completed field to user settings schema, repo, and API
- Create OnboardingContext with auth-aware settings fetch
- Define 9 tour steps targeting data-tour attributes on key UI elements
- Mount Joyride in ChatLayout with dark theme styling
- Add HelpButton component to ChatNav

Signed-off-by: ryaneggz <kre8mymedia@gmail.com>
Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: ryaneggz

backend/src/repos/user_settings_repo.py

@@ -195,6 +195,7 @@ async def set_default_sandbox(self, sandbox: Optional[str]) -> UserSettings:
         "model_visibility": "default_model_visibility",
         "files": "default_files",
         "deleted_files": "default_deleted_files",
+        "onboarding_completed": "onboarding_completed",
     }
 
     async def patch_defaults(self, data: dict) -> UserSettings:

backend/src/routes/v0/settings.py

@@ -33,6 +33,7 @@ def _build_response(settings: UserSettings, statuses: list[ProviderKeyStatus]) -
             model_visibility=settings.default_model_visibility,
             files=settings.default_files,
             deleted_files=settings.default_deleted_files,
+            onboarding_completed=settings.onboarding_completed,
         ),
         provider_keys=statuses,
     )

backend/src/schemas/entities/settings.py

@@ -55,6 +55,9 @@ class UserSettings(BaseEntity):
     default_deleted_files: Optional[list[str]] = Field(
         default=None, description="Absolute file-path tombstones that suppress implicit defaults"
     )
+    onboarding_completed: Optional[bool] = Field(
+        default=None, description="Whether the user has completed the onboarding tour"
+    )
 
 
 class DefaultsResponse(BaseModel):
@@ -69,6 +72,7 @@ class DefaultsResponse(BaseModel):
     model_visibility: Optional[list[str]] = None
     files: Optional[dict[str, PersistedContextFile]] = None
     deleted_files: Optional[list[str]] = None
+    onboarding_completed: Optional[bool] = None
 
 
 class UserSettingsResponse(BaseModel):
@@ -96,6 +100,9 @@ class PatchDefaultsRequest(BaseModel):
         default=None,
         description="Full replacement list of deleted absolute file-path tombstones, or null to clear",
     )
+    onboarding_completed: Optional[bool] = Field(
+        default=None, description="Whether the user has completed the onboarding tour"
+    )
 
 
 class UpsertProviderKeyRequest(BaseModel):