fix(server): transcript key & bump models (#15485)

#### PR Dependency Tree


* **PR #15485** 👈

This tree was auto-generated by
[Charcoal](https://github.com/danerwilliams/charcoal)

<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->

## Summary by CodeRabbit

* **New Features**
* Upgraded built-in AI actions and chat model selection to Gemini 3.7
Flash.
* Transcript attachments now retain storage keys and support secure
presigned URLs during processing.
* Completed transcript results preserve attachment metadata for reliable
access.

* **Bug Fixes**
* Improved transcript handling across uploads, retries, and native
processing.
  * Added safeguards for invalid or missing attachment URLs.

* **Maintenance**
* Added a migration to backfill storage keys for existing transcript
records without altering their URLs.

<!-- end of auto-generated comment: release notes by coderabbit.ai -->

packages/backend/native/src/llm/assets/prompts/built-in.json

@@ -3,8 +3,8 @@
     "name": "Transcript audio",
     "action": "Transcript audio",
     "managedRoute": {
-      "targets": ["gemini-3.5-flash-lite"],
-      "premiumTargets": ["gemini-3.6-flash"]
+      "targets": ["gemini-3.7-flash"],
+      "premiumTargets": ["gemini-3.7-flash"]
     },
     "config": {
       "requireContent": false,
@@ -17,8 +17,8 @@
     "name": "Transcript audio structured",
     "action": "Transcript audio structured",
     "managedRoute": {
-      "targets": ["gemini-3.5-flash-lite"],
-      "premiumTargets": ["gemini-3.6-flash"]
+      "targets": ["gemini-3.7-flash"],
+      "premiumTargets": ["gemini-3.7-flash"]
     },
     "config": {
       "requireContent": false,
@@ -39,7 +39,7 @@
   {
     "name": "Generate a caption",
     "action": "Generate a caption",
-    "managedRoute": { "targets": ["gemini-3.5-flash-lite"] },
+    "managedRoute": { "targets": ["gemini-3.7-flash"] },
     "config": {
       "requireContent": false,
       "requireAttachment": true
@@ -129,7 +129,7 @@
   {
     "name": "Explain this image",
     "action": "Explain this image",
-    "managedRoute": { "targets": ["gemini-3.5-flash-lite"] },
+    "managedRoute": { "targets": ["gemini-3.7-flash"] },
     "config": {
       "requireContent": false,
       "requireAttachment": true
@@ -148,7 +148,7 @@
   {
     "name": "Explain this code",
     "action": "Explain this code",
-    "managedRoute": { "targets": ["gemini-3.5-flash-lite"] },
+    "managedRoute": { "targets": ["gemini-3.7-flash"] },
     "messages": [
       {
         "role": "system",
@@ -163,7 +163,7 @@
   {
     "name": "Translate to",
     "action": "Translate",
-    "managedRoute": { "targets": ["gemini-3.5-flash-lite"] },
+    "managedRoute": { "targets": ["gemini-3.7-flash"] },
     "params": {
       "language": {
         "default": "English",
@@ -256,7 +256,7 @@
   {
     "name": "Write a twitter about this",
     "action": "Write a twitter about this",
-    "managedRoute": { "targets": ["gemini-3.5-flash-lite"] },
+    "managedRoute": { "targets": ["gemini-3.7-flash"] },
     "messages": [
       {
         "role": "system",
@@ -271,7 +271,7 @@
   {
     "name": "Write a poem about this",
     "action": "Write a poem about this",
-    "managedRoute": { "targets": ["gemini-3.5-flash-lite"] },
+    "managedRoute": { "targets": ["gemini-3.7-flash"] },
     "messages": [
       {
         "role": "system",
@@ -301,7 +301,7 @@
   {
     "name": "Write outline",
     "action": "Write outline",
-    "managedRoute": { "targets": ["gemini-3.5-flash-lite"] },
+    "managedRoute": { "targets": ["gemini-3.7-flash"] },
     "messages": [
       {
         "role": "system",
@@ -316,7 +316,7 @@
   {
     "name": "Change tone to",
     "action": "Change tone",
-    "managedRoute": { "targets": ["gemini-3.5-flash-lite"] },
+    "managedRoute": { "targets": ["gemini-3.7-flash"] },
     "params": {
       "tone": {
         "default": "professional",
@@ -337,7 +337,7 @@
   {
     "name": "Brainstorm ideas about this",
     "action": "Brainstorm ideas about this",
-    "managedRoute": { "targets": ["gemini-3.5-flash-lite"] },
+    "managedRoute": { "targets": ["gemini-3.7-flash"] },
     "messages": [
       {
         "role": "system",
@@ -386,7 +386,7 @@
   {
     "name": "Improve writing for it",
     "action": "Improve writing for it",
-    "managedRoute": { "targets": ["gemini-3.5-flash-lite"] },
+    "managedRoute": { "targets": ["gemini-3.7-flash"] },
     "messages": [
       {
         "role": "system",
@@ -416,7 +416,7 @@
   {
     "name": "Fix spelling for it",
     "action": "Fix spelling for it",
-    "managedRoute": { "targets": ["gemini-3.5-flash-lite"] },
+    "managedRoute": { "targets": ["gemini-3.7-flash"] },
     "messages": [
       {
         "role": "system",
@@ -476,7 +476,7 @@
   {
     "name": "Create headings",
     "action": "Create headings",
-    "managedRoute": { "targets": ["gemini-3.5-flash-lite"] },
+    "managedRoute": { "targets": ["gemini-3.7-flash"] },
     "messages": [
       {
         "role": "system",
@@ -521,7 +521,7 @@
   {
     "name": "Make it longer",
     "action": "Make it longer",
-    "managedRoute": { "targets": ["gemini-3.5-flash-lite"] },
+    "managedRoute": { "targets": ["gemini-3.7-flash"] },
     "messages": [
       {
         "role": "system",
@@ -536,7 +536,7 @@
   {
     "name": "Make it shorter",
     "action": "Make it shorter",
-    "managedRoute": { "targets": ["gemini-3.5-flash-lite"] },
+    "managedRoute": { "targets": ["gemini-3.7-flash"] },
     "messages": [
       {
         "role": "system",
@@ -551,7 +551,7 @@
   {
     "name": "Continue writing",
     "action": "Continue writing",
-    "managedRoute": { "targets": ["gemini-3.5-flash-lite"] },
+    "managedRoute": { "targets": ["gemini-3.7-flash"] },
     "messages": [
       {
         "role": "system",
@@ -711,8 +711,8 @@
         },
         {
           "id": "gemini",
-          "modelId": "gemini-3.6-flash",
-          "displayName": "Gemini 3.6 Flash",
+          "modelId": "gemini-3.7-flash",
+          "displayName": "Gemini 3.7 Flash",
           "minimumTier": "premium"
         },
         {

packages/backend/native/src/llm/core/model_registry.rs

@@ -81,12 +81,12 @@ mod tests {
 
     let response = llm_resolve_model_registry_variant(ModelRegistryResolveRequest {
       backend_kind: Some("gemini_api".to_string()),
-      model_id: "gemini-3.6-flash".to_string(),
+      model_id: "gemini-3.7-flash".to_string(),
     })
     .unwrap();
 
     assert_eq!(response.matched_by.as_deref(), Some("raw_model_id"));
-    assert_eq!(response.variant.unwrap().raw_model_id, "gemini-3.6-flash");
+    assert_eq!(response.variant.unwrap().raw_model_id, "gemini-3.7-flash");
   }
 
   #[test]
@@ -301,7 +301,7 @@ mod tests {
         attachment_kinds: None,
         attachment_source_kinds: None,
         has_remote_attachments: None,
-        model_id: Some("gemini-3.6-flash".to_string()),
+        model_id: Some("gemini-3.7-flash".to_string()),
         output_type: Some("image".to_string()),
       },
     })

packages/backend/native/src/llm/core/request_builder/mod.rs

@@ -210,7 +210,7 @@ mod tests {
   fn should_materialize_structured_request_with_response_contract() {
     let response = llm_build_canonical_structured_request(
       serde_json::from_value::<CanonicalStructuredRequestContract>(json!({
-        "model": "gemini-3.6-flash",
+        "model": "gemini-3.7-flash",
         "messages": [
           { "role": "user", "content": "hello" }
         ],
@@ -226,7 +226,7 @@ mod tests {
     assert_eq!(
       response,
       json!({
-        "model": "gemini-3.6-flash",
+        "model": "gemini-3.7-flash",
         "messages": [
           {
             "role": "user",

packages/backend/native/src/llm/prompt_catalog.rs

@@ -597,13 +597,13 @@ mod tests {
     );
 
     let transcript = built_in_prompt("Transcript audio structured").expect("transcript prompt");
-    assert_eq!(transcript.managed_targets, ["gemini-3.5-flash-lite"]);
+    assert_eq!(transcript.managed_targets, ["gemini-3.7-flash"]);
     assert_eq!(
       transcript
         .managed_premium_targets
         .as_deref()
         .map(|targets| targets.iter().map(String::as_str).collect::<Vec<_>>()),
-      Some(vec!["gemini-3.6-flash"])
+      Some(vec!["gemini-3.7-flash"])
     );
   }
 }

packages/backend/native/src/llm/route/catalog.rs

@@ -262,7 +262,7 @@ mod tests {
         CopilotManagedTier::Premium
       )
       .unwrap(),
-      ["gemini-3.6-flash"]
+      ["gemini-3.7-flash"]
     );
     assert_eq!(
       managed_targets(&slot("index.embedding").unwrap(), None, CopilotManagedTier::Standard).unwrap(),

packages/backend/native/src/runtime/backend_runtime/copilot/context.rs

@@ -326,7 +326,7 @@ mod tests {
       id: "vertex".to_string(),
       provider: "geminiVertex".to_string(),
       enabled: true,
-      models: vec!["gemini-3.6-flash".to_string()],
+      models: vec!["gemini-3.7-flash".to_string()],
       config: json!({ "project": "affine-us", "location": location }),
     }
   }