agent: default autoDiscover to enabled

Updates the agent discovers handler to default capture `autoDiscover` to
enabled. If there is an existing capture spec, then its `autoDiscover` property
(or lack thereof) is used directly. But if discovering a new capture, then
`autoDiscover` will be enabled.

crates/agent/src/discovers/snapshots/agent__discovers__specs__tests__capture_merge_create.snap

@@ -4,6 +4,10 @@ expression: json!(out)
 ---
 [
   {
+    "autoDiscover": {
+      "addNewBindings": true,
+      "evolveIncompatibleCollections": false
+    },
     "bindings": [
       {
         "resource": {

crates/agent/src/discovers/specs.rs

@@ -51,7 +51,10 @@ pub fn merge_capture(
             Vec::new(),
             models::CaptureDef::default_interval(),
             models::ShardTemplate::default(),
-            None,
+            Some(models::AutoDiscover {
+                add_new_bindings: true,
+                evolve_incompatible_collections: false,
+            }),
         ),
     };
 

crates/models/src/captures.rs

@@ -46,12 +46,12 @@ pub struct CaptureDef {
 pub struct AutoDiscover {
     /// Automatically add new bindings discovered from the source.
     #[serde(default)]
-    add_new_bindings: bool,
+    pub add_new_bindings: bool,
     /// Whether to automatically evolve collections and/or materialization
     /// bindings to handle changes to collections that would otherwise be
     /// incompatible with the existing catalog.
     #[serde(default)]
-    evolve_incompatible_collections: bool,
+    pub evolve_incompatible_collections: bool,
 }
 
 /// An endpoint from which Flow will capture.

crates/models/src/lib.rs

@@ -18,7 +18,7 @@ mod source;
 mod tests;
 
 pub use crate::labels::{Label, LabelSelector, LabelSet};
-pub use captures::{CaptureBinding, CaptureDef, CaptureEndpoint};
+pub use captures::{AutoDiscover, CaptureBinding, CaptureDef, CaptureEndpoint};
 pub use catalogs::Catalog;
 pub use collections::{CollectionDef, Projection};
 pub use connector::ConnectorConfig;