feat(designs): Create designs folder (strands-agents#487)

Author: mkmeral

designs/README.md

@@ -0,0 +1,85 @@
+# Design Documents
+
+This folder contains design documents for significant features and changes to Strands Agents. These documents capture the context, decision, and consequences of architectural choices.
+
+For lightweight architecture decision records, see [DECISIONS.md](../team/DECISIONS.md).
+
+## What is a design document?
+
+A design document proposes a significant change or new feature. It describes the problem, proposed solution, and tradeoffs. Once approved and merged, it becomes an accepted design and part of the project's decision history.
+
+## When to write a design document
+
+Write a design document for:
+
+- New major features affecting multiple parts of the SDK
+- Breaking changes to existing APIs
+- Architectural changes requiring design discussion
+- Large contributions (> 1 week of work)
+- Features that introduce new concepts
+
+Skip the design process for bug fixes, small improvements, documentation updates, and new extensions in your own repository.
+
+## How to submit a feature proposal
+
+1. **Check the [roadmap](https://github.com/orgs/strands-agents/projects/8/views/1)** — See if your idea aligns with our direction
+2. **Fork the [docs repository](https://github.com/strands-agents/docs)**
+3. **Create your design** — Add a new file: `designs/NNNN-feature-name.md` using the template below
+4. **Submit a pull request** — We'll review and discuss
+5. **Iterate based on feedback** — Address comments and questions
+6. **Get approval** — Once approved and merged, implement the feature
+7. **Reference the design** — Link to it in your implementation PR
+
+## Design document template
+
+```markdown
+# [Feature Name]
+
+**Status**: Proposed | Accepted | Deprecated | Superseded
+
+**Date**: YYYY-MM-DD
+
+**Issue**: Issue Link
+
+## Context
+
+What is the issue that we're seeing that is motivating this decision or change?
+
+- What task are you trying to accomplish?
+- What makes it difficult or impossible today?
+- Who experiences this problem?
+
+## Decision
+
+What is the change that we're proposing and/or doing?
+
+- Changes to the API (with code examples)
+- How it integrates with existing features
+- Expected behavior and usage patterns
+
+## Developer Experience
+
+Show what the developer experience looks like:
+
+- Code examples showing typical usage
+- Configuration or setup required
+- Error messages and edge cases
+
+## Alternatives Considered
+
+What other approaches did you consider? Why did you choose this one?
+
+## Consequences
+
+What becomes easier or more difficult to do because of this change?
+
+## Willingness to Implement
+
+Are you willing to implement this if approved?
+
+Yes / No / Maybe with guidance
+```
+
+## Accepted Designs
+
+*No designs have been accepted yet.*