Add Rust SDK examples and activity definition code tabs (#4565)

* Add Rust SDK examples and activity definition code tabs

* Add WorkflowContext import to Rust workflow definition

Author: jsundai

docs/encyclopedia/activities/activity-definition.mdx

@@ -33,12 +33,146 @@ Temporal documentation aims to be explicit and differentiate between them.
 An Activity Definition is the code that defines the constraints of an [Activity Task Execution](/tasks#activity-task-execution).
 Activities encapsulate business logic that is prone to failure, allowing for automatic retries when issues occur.
 
+Below are examples of basic Activity Definitions across supported SDKs.
+
+<Tabs groupId="basic-activity-definition" queryString>
+<TabItem value="go" label="Go">
+
+**[Activity Definition in Go](/develop/go/activities/basics)**
+
+```go
+import (
+    "context"
+
+    "go.temporal.io/sdk/activity"
+)
+
+func YourSimpleActivity(ctx context.Context) error {
+    return nil
+}
+```
+
+</TabItem>
+<TabItem value="java" label="Java">
+
+**[Activity Definition in Java (Interface)](/develop/java/activities/basics)**
+
+```java
+@ActivityInterface
+public interface GreetingActivities {
+    @ActivityMethod
+    String composeGreeting(String greeting, String language);
+}
+```
+
+**[Activity Definition in Java (Implementation)](/develop/java/activities/basics)**
+
+```java
+static class GreetingActivitiesImpl implements GreetingActivities {
+    @Override
+    public String composeGreeting(String greeting, String name) {
+        return greeting + " " + name + "!";
+    }
+}
+```
+
+</TabItem>
+<TabItem value="php" label="PHP">
+
+**[Activity Definition in PHP (Interface)](/develop/php/activities/basics)**
+
+```php
+#[ActivityInterface]
+interface GreetingActivities
+{
+    public function composeGreeting(string $greeting, string $name): string;
+}
+```
+
+**[Activity Definition in PHP (Implementation)](/develop/php/activities/basics)**
+
+```php
+class GreetingActivitiesImpl implements GreetingActivities
+{
+    public function composeGreeting(string $greeting, string $name): string
+    {
+        return $greeting . ' ' . $name;
+    }
+}
+```
+
+</TabItem>
+<TabItem value="python" label="Python">
+
+**[Activity Definition in Python](/develop/python/activities/basics)**
+
+```python
+from temporalio import activity
+
+@activity.defn(name="your_activity")
+async def your_activity(input: YourParams) -> str:
+    return f"{input.greeting}, {input.name}!"
+```
+
+</TabItem>
+<TabItem value="typescript" label="TypeScript">
+
+**[Activity Definition in TypeScript](/develop/typescript/activities/basics)**
+
+```ts
+export async function greet(name: string): Promise<string> {
+  return `Hello, ${name}!`;
+}
+```
+
+</TabItem>
+<TabItem value="dotnet" label=".NET">
+
+**[Activity Definition in C# and .NET](/develop/dotnet/activities/basics)**
+
+```csharp
+using Temporalio.Activities;
+
+public class MyActivities
+{
+    [Activity]
+    public string MyActivity(MyActivityParams input) =>
+        $"{input.Greeting}, {input.Name}!";
+}
+```
+
+</TabItem>
+<TabItem value="rust" label="Rust">
+
+**[Activity Definition in Rust](/develop/rust/activities/basics)**
+
+```rust
+use temporalio_sdk::activities::{ActivityContext, ActivityError};
+use temporalio_macros::activities;
+
+pub struct GreetingActivities;
+
+#[activities]
+impl GreetingActivities {
+    #[activity]
+    pub async fn greet(_ctx: ActivityContext, name: String) -> Result<String, ActivityError> {
+        Ok(format!("Hello, {}!", name))
+    }
+}
+```
+
+</TabItem>
+</Tabs>
+
+For full SDK-specific guides, see:
+
 - [How to develop an Activity Definition using the Go SDK](/develop/go/activities/basics)
 - [How to develop an Activity Definition using the Java SDK](/develop/java/activities/basics)
 - [How to develop an Activity Definition using the PHP SDK](/develop/php/activities/basics)
 - [How to develop an Activity Definition using the Python SDK](/develop/python/activities/basics)
 - [How to develop an Activity Definition using the TypeScript SDK](/develop/typescript/activities/basics)
 - [How to develop an Activity Definition using the .NET SDK](/develop/dotnet/activities/basics)
+- [How to develop an Activity Definition using the Rust SDK](/develop/rust/activities/basics)
 
 The term 'Activity Definition' is used to refer to the full set of primitives in any given language SDK that provides an access point to an Activity Function Definition——the method or function that is invoked for an [Activity Task Execution](/tasks#activity-task-execution).
 Therefore, the terms Activity Function and Activity Method refer to the source of an instance of an execution.

docs/encyclopedia/workflow/workflow-definition.mdx

@@ -143,6 +143,35 @@ public class YourBasicWorkflow {
 }
 ```
 
+</TabItem>
+<TabItem value="rust" label="Rust">
+
+**[Workflow Definition in Rust](/develop/rust/workflows/basics)**
+
+```rust
+use temporalio_macros::{workflow, workflow_methods};
+use temporalio_sdk::{WorkflowContext, WorkflowContextView, WorkflowResult};
+
+#[workflow]
+pub struct YourBasicWorkflow {
+    param: String,
+}
+
+#[workflow_methods]
+impl YourBasicWorkflow {
+    #[init]
+    fn new(_ctx: &WorkflowContextView, param: String) -> Self {
+        Self { param }
+    }
+
+    #[run]
+    async fn run(ctx: &mut WorkflowContext<Self>) -> WorkflowResult<String> {
+        // ...
+        Ok(String::new())
+    }
+}
+```
+
 </TabItem>
 
 </Tabs>