Require accepting ToS when enabling zeta (#23255)

Note: Design hasn't been reviewed yet, but the logic is done

When the user switches the inline completion provider to `zed`, we'll
show a modal prompting them to accept terms if they haven't done so:


https://github.com/user-attachments/assets/3fc6d368-c00a-4dcb-9484-fbbbb5eb859e

If they dismiss the modal, they'll be able to get to it again from the
inline completion button:


https://github.com/user-attachments/assets/cf842778-5538-4e06-9ed8-21579981cc47

This also stops zeta sending requests that will fail immediately when
ToS are not accepted.

Release Notes:

- N/A

---------

Co-authored-by: Richard <richard@zed.dev>
Co-authored-by: Danilo Leal <daniloleal09@gmail.com>
Co-authored-by: Joao <joao@zed.dev>

Cargo.lock

@@ -3959,6 +3959,7 @@ dependencies = [
  "util",
  "uuid",
  "workspace",
+ "zed_predict_tos",
 ]
 
 [[package]]
@@ -6304,6 +6305,7 @@ name = "inline_completion_button"
 version = "0.1.0"
 dependencies = [
  "anyhow",
+ "client",
  "copilot",
  "editor",
  "feature_flags",
@@ -6323,6 +6325,7 @@ dependencies = [
  "ui",
  "workspace",
  "zed_actions",
+ "zed_predict_tos",
  "zeta",
 ]
 
@@ -16337,6 +16340,7 @@ dependencies = [
  "winresource",
  "workspace",
  "zed_actions",
+ "zed_predict_tos",
  "zeta",
 ]
 
@@ -16450,6 +16454,17 @@ dependencies = [
  "zed_extension_api 0.1.0",
 ]
 
+[[package]]
+name = "zed_predict_tos"
+version = "0.1.0"
+dependencies = [
+ "client",
+ "gpui",
+ "menu",
+ "ui",
+ "workspace",
+]
+
 [[package]]
 name = "zed_prisma"
 version = "0.0.4"