Remove Warp cloud features and OpenTelemetry

Settings cleanup:
- Remove billing_and_usage, main_page, referrals_page, show_blocks_view,
  environments_page, handoff_environment_creation_modal,
  custom_inference_modal, remove_custom_endpoint_confirmation_dialog,
  transfer_ownership_confirmation_modal, delete_environment_confirmation_dialog
- Remove SettingsSection variants: Account, BillingAndUsage, Referrals,
  SharedBlocks, CloudEnvironments, OzCloudAPIKeys
- Remove SettingsPageViewHandle variants: Main, BillingAndUsage, Referrals,
  CloudEnvironments, OzCloudAPIKeys, SharedBlocks
- Add Platform variant for PlatformPageView
- Gut custom inference endpoint UI from ai_page.rs
- Gut transfer ownership modal from teams_page.rs
- Stub environment_management_pane as dead code
- Remove create_discount_badge usage
- Remove handle_experiment_change call

OpenTelemetry removal:
- Remove opentelemetry, opentelemetry-http, opentelemetry-otlp,
  opentelemetry_sdk, tracing-opentelemetry dependencies
- Replace tracing module with no-op stub
- Delete native.rs and cloud_agent_auth.rs

Bug fixes (prior work):
- Fix apply_diffs() to use markdown_unescaped(ctx)
- Fix notebook executor AIDocumentId handling
- Fix margin/corner-radius consistency in requested_command.rs
- Add document tool handlers to extract_tool_result_content()
- Fix deprecated from_byte_stream in MCP SSE transport
- Fix Cargo.toml profile package spec
- Upgrade rust-toolchain to 1.94.1

app/src/uri/mod.rs

@@ -405,7 +405,7 @@ impl UriHost {
                                 primary_window_id,
                                 "root_view:open_settings_page_in_existing_window",
                                 "root_view:open_settings_page_in_new_window",
-                                &SettingsSection::CloudEnvironments,
+                                &SettingsSection::About,
                                 ctx,
                             );
                         }
@@ -1631,8 +1631,8 @@ fn dispatch_action_in_new_or_existing_window<T: 'static>(
 
 fn settings_section_for_simple_subpage(subpage: &str) -> Option<SettingsSection> {
     match subpage {
-        "billing_and_usage" => Some(SettingsSection::BillingAndUsage),
-        "platform" => Some(SettingsSection::OzCloudAPIKeys),
+        "billing_and_usage" => Some(SettingsSection::About),
+        "platform" => Some(SettingsSection::About),
         "appearance" => Some(SettingsSection::Appearance),
         "warp_agent" => Some(SettingsSection::WarpAgent),
         _ => None,