docs: consolidate Copilot instructions and fix workflow trigger

.github/copilot-instructions.md

@@ -2,11 +2,33 @@
 
 > **Note**: For general development guidelines, code style conventions, and AI agent instructions, see [`AGENTS.md`](../AGENTS.md) in the repository root.
 
+## Project Overview
+
+igraph/rigraph is an R package for network analysis and graph theory with a C/C++ backend.
+
 ## Common Commands for Copilot Chat
 
 - Load for development: `pkgload::load_all()`
 - Run tests: `testthat::test_local(reporter = "check")`
+- Run tests for a single file: `testthat::test_local(filter = "foo", reporter = "check")`
 - Format code: `air format .`
 - Update documentation: `devtools::document()`
+- Build package: `devtools::build()`
+- Check package: `devtools::check()`
+
+## Key Conventions
+
+- Use `snake_case` for functions and arguments
+- Follow tidyverse style guide
+- Use roxygen2 with Markdown for documentation
+- Run `air format .` before committing
+- Add tests for all new functionality
+- Use explicit package prefixes (e.g., `withr::local_db_connection()`)
+
+## Important Files
+
+- **Do not modify directly**: `src/rinterface.c`, `R/aaa-auto.R` (generated by Stimulus)
+- Update generated files: `make -f Makefile-cigraph src/rinterface.c R/aaa-auto.R`
+- See `tools/README.md` for Stimulus framework guidelines
 
-Refer to `AGENTS.md` for more instructions.
+Refer to `AGENTS.md` for complete instructions.

.github/workflows/copilot-setup-steps.yaml

@@ -6,10 +6,10 @@ on:
   workflow_dispatch:
   push:
     paths:
-      - .github/workflows/copilot-setup-steps.yml
+      - .github/workflows/copilot-setup-steps.yaml
   pull_request:
     paths:
-      - .github/workflows/copilot-setup-steps.yml
+      - .github/workflows/copilot-setup-steps.yaml
 
 jobs:
   # The job MUST be called `copilot-setup-steps` or it will not be picked up by Copilot.