fix(hermes): prevent YAML pollution and drop of OAuth mcp auth

DeepLink Hermes import was emitting camelCase (baseUrl / apiKey /
apiMode) that the Hermes runtime does not recognise, poisoning
`custom_providers:` entries on activation. The MCP sync path was
also stripping `auth: oauth` on round-trip, silently downgrading
OAuth-type servers to unauthenticated calls.

The Hermes deeplink branch now emits snake_case via a dedicated
builder; `sanitize_hermes_provider_keys` runs on both `set_provider`
and `get_providers` so legacy DB records heal on next access.
`HERMES_EXTRA_FIELDS` preserves `auth`. The `api_mode` dropdown gains
`codex_responses` (Copilot / OpenCode), and the schema-migrated
warning copy no longer hard-codes "v12" (upstream `_config_version`
is now 19).

src-tauri/src/deeplink/mod.rs

@@ -31,7 +31,7 @@ pub use skill::import_skill_from_deeplink;
 ///
 /// Represents a parsed ccswitch:// URL ready for processing.
 /// This struct contains all possible fields for all resource types.
-#[derive(Debug, Clone, Serialize, Deserialize)]
+#[derive(Debug, Clone, Default, Serialize, Deserialize)]
 #[serde(rename_all = "camelCase")]
 pub struct DeepLinkImportRequest {
     /// Protocol version (e.g., "v1")