Add README for cmd/samples/recipes/greetings

Signed-off-by: Diana Zawadzki <[email protected]>

Author: zawadzkidiana

cmd/samples/recipes/greetings/README.md

@@ -0,0 +1,85 @@
+# Greetings Sample
+
+This sample demonstrates **sequential activity execution** - running multiple activities one after another, passing results between them.
+
+> **Looking for a visual guide?** See [new_samples/hello_world](../../../../new_samples/hello_world/) for a step-by-step tutorial with screenshots.
+
+
+## How It Works
+
+The workflow executes 3 activities in sequence:
+
+```
+┌─────────────────┐    ┌─────────────────┐    ┌─────────────────────┐
+│ getGreeting()   │───▶│ getName()       │───▶│ sayGreeting(g, n)   │
+│ returns "Hello" │    │ returns "Cadence"│    │ returns "Hello      │
+└─────────────────┘    └─────────────────┘    │          Cadence!"  │
+                                              └─────────────────────┘
+```
+
+## Prerequisites
+
+1. Cadence server running (see [main README](../../../../README.md))
+2. Build the samples:
+   ```bash
+   make
+   ```
+
+## Running the Sample
+
+### Step 1: Start the Worker
+
+```bash
+./bin/greetings -m worker
+```
+
+### Step 2: Trigger the Workflow
+
+```bash
+./bin/greetings -m trigger
+```
+
+### Step 3: View the Result
+
+Check the worker terminal:
+```
+Workflow completed. {"Result": "Greeting: Hello Cadence!\n"}
+```
+
+Or view in the Cadence Web UI at [localhost:8088](http://localhost:8088).
+
+## Key Code
+
+### Sequential Execution Pattern
+
+```go
+// Activity 1: Get greeting
+var greetResult string
+err := workflow.ExecuteActivity(ctx, getGreetingActivity).Get(ctx, &greetResult)
+
+// Activity 2: Get name
+var nameResult string
+err = workflow.ExecuteActivity(ctx, getNameActivity).Get(ctx, &nameResult)
+
+// Activity 3: Combine results
+var sayResult string
+err = workflow.ExecuteActivity(ctx, sayGreetingActivity, greetResult, nameResult).Get(ctx, &sayResult)
+```
+
+Each `ExecuteActivity().Get()` blocks until the activity completes, ensuring sequential execution.
+
+## Testing
+
+```bash
+# Unit tests
+go test -v ./cmd/samples/recipes/greetings/ -run TestUnitTestSuite
+
+# Replay tests
+go test -v ./cmd/samples/recipes/greetings/ -run TestReplayWorkflowHistoryFromFile
+```
+
+## References
+
+- [Cadence Documentation](https://cadenceworkflow.io)
+- [Activity Basics](https://cadenceworkflow.io/docs/concepts/activities/)
+