add template for concepts

On-behalf-of: Gerald Morrison (SAP) <gerald.morrison@sap.com>
Signed-off-by: Gerald Morrison (SAP) <gerald.morrison@sap.com>

Author: morrison-sap

content_templates/template-concept.md

@@ -0,0 +1,109 @@
+---
+title: "TEMPLATE: Concept Title"
+description: "What [concept] is and why it matters in OCM."
+weight: 999
+toc: true 
+hasMermaid: true
+---
+
+## What is [Concept]?
+
+Write 2–4 sentences answering: *What is this? What problem does it solve? Where does it fit in OCM?*
+
+Avoid "how to configure" or step-by-step instructions here. This section builds the mental model.
+
+> **Example:** A resolver maps component name patterns to OCM repositories. When OCM encounters a component reference during recursive resolution, it consults the configured resolvers to locate the right repository — without requiring the caller to know where each component lives.
+
+## Why does it exist?
+
+Explain the design rationale. What would be harder or impossible without this concept?
+
+Use 1–3 short paragraphs or a brief list of motivations.
+
+- **Motivation 1:** Why this was needed
+- **Motivation 2:** What alternative it replaces or improves
+- **Motivation 3:** What constraint or use case it addresses
+
+## How it works
+
+Explain the underlying mechanics — not how to *use* it, but how it *works internally*.
+Use a diagram to build a clear mental model:
+
+```mermaid
+flowchart LR
+    A[Input] --> B[Concept mechanism]
+    B --> C[Output / Effect]
+```
+
+Describe the diagram in 2–4 sentences. Walk through the key parts and their relationships.
+
+### [Sub-concept or aspect A]
+
+Explain one distinct aspect of the concept in depth. Use subsections to separate orthogonal concerns.
+
+### [Sub-concept or aspect B]
+
+Continue with the next aspect.
+
+{{< callout type="note" >}}
+Highlight any non-obvious behavior, edge cases, or important constraints that affect how this concept works.
+{{< /callout >}}
+
+## Key properties
+
+Summarize the defining characteristics that readers should remember.
+
+| Property | Description |
+|----------|-------------|
+| **[Property 1]** | What it means and why it matters |
+| **[Property 2]** | What it means and why it matters |
+| **[Property 3]** | What it means and why it matters |
+
+## Relationship to other concepts
+
+Explain how this concept connects to, extends, or depends on other OCM concepts.
+Keep this conceptual — link to the other concept docs instead of repeating their content.
+
+- **[Related Concept A]({{< relref "docs/concepts/<file>.md" >}})** — How they relate (e.g., "Resolvers depend on OCM Repositories as their resolution targets")
+- **[Related Concept B]({{< relref "docs/concepts/<file>.md" >}})** — How they relate
+
+## When to use it
+
+Describe the scenarios in which this concept is relevant. Help readers recognize *when* they are dealing with this concept.
+
+- Use **[Concept]** when you need to…
+- It becomes important when…
+- You can ignore it if…
+
+{{< callout type="tip" >}}
+If this concept has common misconceptions, address them here briefly.
+{{< /callout >}}
+
+## Next steps
+
+- [How-to: <name>]({{< relref "docs/how-to/<file>.md" >}})
+
+## Related documentation
+
+- [Concept: <name>]({{< relref "docs/concepts/<file>.md" >}})
+- [Tutorial: <name>]({{< relref "docs/tutorials/<file>.md" >}})
+- [Reference: <command>]({{< relref "docs/reference/<file>.md" >}})
+
+---
+
+## ✓ Before publishing
+
+Make sure to comply with our [CONTRIBUTING guide](../CONTRIBUTING.md),
+check the [Concept Writing Checklist](../CONTRIBUTING.md#concept-checklist),
+and ensure the following:
+
+- [ ] Title is a noun or noun phrase — not a verb or task (e.g., "Resolvers", not "How to use resolvers")
+- [ ] Description answers "what is it and why does it matter"
+- [ ] No step-by-step instructions — link to How-tos or Tutorials instead
+- [ ] Explains *why* the concept exists, not just *what* it is
+- [ ] Uses a diagram to build a mental model (Mermaid preferred)
+- [ ] Subsections address distinct orthogonal aspects
+- [ ] "Relationship to other concepts" section with relref links
+- [ ] "When to use it" section helps readers self-identify relevance
+- [ ] No CLI commands that constitute a workflow (short illustrative snippets are OK)
+- [ ] Working `relref` links throughout