Docs: Add copilot config, extract shared agent workflow guidelines

Create .github/copilot-instructions.md as a minimal GitHub Copilot entry point, trim CLAUDE.md to a minimal pointer file, and move shared safety/output-expectation guidance into docs/agents/workflow.md. Also update the header/implementation-split rule in docs/agents/coding-style.md to allow short one-line bodies and short initializer lists inline in the header.

.github/copilot-instructions.md

@@ -0,0 +1,15 @@
+# GitHub Copilot Instructions
+
+You are an automated contributor to the ResInsight repository.
+
+## Source of Truth
+
+You MUST follow the canonical agent guidelines located in the `docs/agents/` directory:
+
+- **[docs/agents/core.md](../docs/agents/core.md)** - Core agent guidelines, architecture overview, PDM system, Python integration
+- **[docs/agents/build.md](../docs/agents/build.md)** - Build system, prerequisites, test commands
+- **[docs/agents/coding-style.md](../docs/agents/coding-style.md)** - Code formatting, style conventions
+- **[docs/agents/repo-map.md](../docs/agents/repo-map.md)** - Repository structure and file locations
+- **[docs/agents/workflow.md](../docs/agents/workflow.md)** - Safety guidelines and output expectations
+
+These documents contain the authoritative information about the project. Always consult them when working on code.

CLAUDE.md

@@ -10,57 +10,8 @@ You MUST follow the canonical agent guidelines located in the `docs/agents/` dir
 - **[docs/agents/build.md](docs/agents/build.md)** - Build system, prerequisites, test commands
 - **[docs/agents/coding-style.md](docs/agents/coding-style.md)** - Code formatting, style conventions
 - **[docs/agents/repo-map.md](docs/agents/repo-map.md)** - Repository structure and file locations
+- **[docs/agents/workflow.md](docs/agents/workflow.md)** - Safety guidelines and output expectations
 
 These documents contain the authoritative information about the project. Always consult them when working on code.
 
-## Claude-Specific Rules
-
-### Change Philosophy
-- Prefer minimal diffs - make the smallest possible changes to achieve the goal
-- Do not reformat unrelated code
-- Preserve existing code style and comments
-- Only modify files directly related to your task
-
-### Safety Guidelines
-- Never modify CI/CD configuration unless explicitly asked
-- Always validate changes don't break existing behavior
-- Always validate changes don't introduce security vulnerabilities
-- If unsure about a change, stop and explain the uncertainty to the user
-
-### Testing
-- Run existing linters and tests before making changes
-- Run linters and tests after making changes
-- Do not add new testing tools unless necessary
-- Do not remove or modify unrelated tests
-
-## Output Expectations
-
-### Before Making Changes
-- Explain your reasoning and approach
-- List the specific files that will be modified
-- Describe the expected impact of the changes
-
-### When Making Changes
-- Make incremental, focused changes
-- Test each change before proceeding
-- Report progress frequently using the `report_progress` tool
-
-### After Making Changes
-- Verify the changes work as expected
-- Run relevant tests and linters
-- Document any issues or limitations discovered
-
-## Working with Python
-
-When working with Python code:
-- Always format code with `ruff format`
-- Always check style with `ruff check --fix`
-- Run these before committing changes
-
-## Commit Messages
-
-Follow these conventions:
-- Start with issue number: `#12773 Python: Add API for creating valve templates`
-- Use standard git commit message format
-- Only use line breaks between paragraphs in the description
-- Keep first line concise and descriptive
+Use `report_progress` to report progress frequently while working.

docs/agents/coding-style.md

@@ -46,7 +46,7 @@ python -m ruff check --fix test_polygons.py
 
 1. **Minimal Changes**: Make the smallest possible changes to achieve the goal
 2. **Preserve Formatting**: Do not reformat unrelated code
-3. **Comments**: Match the style of existing comments in the file
+3. **Comments**: Match the style of existing comments in the file, keep them concise and as short as possible while still being clear
 4. **Libraries**: Use existing libraries whenever possible; only add new libraries or update versions if absolutely necessary
 
 ### Code Quality
@@ -69,17 +69,27 @@ python -m ruff check --fix test_polygons.py
 Put function bodies in the `.cpp` file, not inline in the header.
 
 - Declare member functions in the header; define them in the matching `.cpp`.
-- This applies even to one-line bodies (`return false;`, `return m_field;`, trivial forwarders).
-- Exceptions: function templates that must stay in the header, and `constexpr` functions where the compiler requires the definition to be visible.
+- Exceptions: function templates that must stay in the header, `constexpr` functions where the compiler requires the definition to be visible, and functions with an empty body (`{}`) or a short initializer list.
 
 ```cpp
-// Bad – inline body in the header
+// OK – short one-line body allowed inline
 class RimFoo
 {
 public:
     bool canAddSubCollection() const override { return false; }
 };
 
+// Bad – multi-statement body inline in the header
+class RimFoo
+{
+public:
+    bool canAddSubCollection() const override
+    {
+        if ( m_locked ) return false;
+        return m_children.empty();
+    }
+};
+
 // Good – declared in the header, defined in the .cpp
 // RimFoo.h
 class RimFoo
@@ -91,8 +101,23 @@ public:
 // RimFoo.cpp
 bool RimFoo::canAddSubCollection() const
 {
-    return false;
+    if ( m_locked ) return false;
+    return m_children.empty();
 }
+
+// OK – empty body / short initializer list allowed inline
+class RimBar
+{
+public:
+    void reset() {}
+    RimBar( int value )
+        : m_value( value )
+    {
+    }
+
+private:
+    int m_value = 0;
+};
 ```
 
 Why: keeps headers light (faster builds, smaller include surface), keeps the implementation file as the single source of truth for behavior, and matches the existing style across `ApplicationLibCode`.

docs/agents/workflow.md

@@ -0,0 +1,27 @@
+# Agent Workflow Guidelines
+
+This document describes how AI agents should operate when making changes to ResInsight.
+
+## Safety Guidelines
+
+- Never modify CI/CD configuration unless explicitly asked
+- Always validate changes don't break existing behavior
+- Always validate changes don't introduce security vulnerabilities
+- If unsure about a change, stop and explain the uncertainty to the user
+
+## Output Expectations
+
+### Before Making Changes
+- Explain your reasoning and approach
+- List the specific files that will be modified
+- Describe the expected impact of the changes
+
+### When Making Changes
+- Make incremental, focused changes
+- Test each change before proceeding
+- Report progress frequently
+
+### After Making Changes
+- Verify the changes work as expected
+- Run relevant tests and linters
+- Document any issues or limitations discovered