assistant2: Add ability to configure tools for profiles in the UI (#27562)

This PR adds the ability to configure tools for a profile in the UI:


https://github.com/user-attachments/assets/16642f14-8faa-4a91-bb9e-1d480692f1f2

Note: Doesn't yet work for customizing tools for the default profiles.

Release Notes:

- N/A

crates/assistant_settings/src/agent_profile.rs

@@ -12,7 +12,7 @@ pub struct AgentProfile {
     pub context_servers: IndexMap<Arc<str>, ContextServerPreset>,
 }
 
-#[derive(Debug, Clone)]
+#[derive(Debug, Clone, Default)]
 pub struct ContextServerPreset {
     pub tools: IndexMap<Arc<str>, bool>,
 }

crates/assistant_settings/src/assistant_settings.rs

@@ -442,7 +442,7 @@ pub struct AgentProfileContent {
     pub context_servers: IndexMap<Arc<str>, ContextServerPresetContent>,
 }
 
-#[derive(Debug, PartialEq, Clone, Serialize, Deserialize, JsonSchema)]
+#[derive(Debug, PartialEq, Clone, Default, Serialize, Deserialize, JsonSchema)]
 pub struct ContextServerPresetContent {
     pub tools: IndexMap<Arc<str>, bool>,
 }