Migrate GitHub Copilot agent config from .github/copilot-instructions.md to AGENTS.md

[Copilot]

GitHub Copilot now supports the AGENTS.md standard, making .github/copilot-instructions.md redundant. This aligns Copilot with the shared AGENTS.md file already used by Codex and OpenCode, reducing duplication.

Core change

models/AgentRegistry.cfc — copilot path updated in both AGENT_FILES and getAgentConfigPath():

AGENT_FILES = {
    "claude"   : "CLAUDE.md",
    "copilot"  : "AGENTS.md",   // was: ".github/copilot-instructions.md"
    "cursor"   : ".cursorrules",
    "codex"    : "AGENTS.md",
    "gemini"   : "GEMINI.md",
    "opencode" : "AGENTS.md"
}

Supporting updates

• commands/coldbox/ai/agents/help.cfc — help text updated to show AGENTS.md (shared) for Copilot
• AI_INTEGRATION.md — agent table, mermaid diagrams, setup instructions, and agent file list updated; duplicate AGENTS.md entry removed
• README.md — supported agents list updated
• changelog.md — new entry added noting that existing .github/copilot-instructions.md files are not auto-removed on coldbox ai refresh

[Copilot]

Pull request overview

This PR migrates the GitHub Copilot agent configuration file used by the ColdBox CLI from the legacy .github/copilot-instructions.md location to the newer AGENTS.md standard, aligning Copilot with other agents that already use the shared AGENTS.md file.

Changes:

• Updated AgentRegistry to map Copilot’s config file to AGENTS.md (and return that path from getAgentConfigPath()).
• Updated CLI help and documentation to reflect Copilot using AGENTS.md (shared).
• Added changelog notes about the migration and updated supported-agent listings.

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
models/AgentRegistry.cfc	Switches Copilot config path to AGENTS.md in both the registry mapping and path resolution.
commands/coldbox/ai/agents/help.cfc	Updates agent help text to show Copilot uses AGENTS.md (shared).
AI_INTEGRATION.md	Updates diagrams/table/setup steps to reflect Copilot using shared AGENTS.md.
README.md	Updates supported agents list to reflect Copilot’s new config file location.
changelog.md	Adds an Unreleased entry documenting the Copilot → AGENTS.md migration and updates supported agents text.

Comments suppressed due to low confidence (2)

AI_INTEGRATION.md:958

• This diagram now labels Copilot as "AGENTS.md (shared)" but still shows separate AGENTS.md nodes for Codex/OpenCode. If AGENTS.md is truly shared among these agents, consider modeling them as pointing to the same AGENTS.md node (or labeling Codex/OpenCode nodes as shared too) to prevent confusion.

    subgraph "Agent Configurations"
        Guidelines --> ClaudeConfig["CLAUDE.md"]
        Guidelines --> CopilotConfig["AGENTS.md (shared)"]
        Guidelines --> CursorConfig[".cursorrules"]
        Guidelines --> CodexConfig["AGENTS.md"]
        Guidelines --> GeminiConfig["GEMINI.md"]
        Guidelines --> OpenCodeConfig["AGENTS.md"]

models/AgentRegistry.cfc:29

• copilot, codex, and opencode now all resolve to the same config path (AGENTS.md). The existing coldbox ai agents remove <agent> implementation deletes the file returned by getAgentConfigPath(), so removing any one of these agents will delete AGENTS.md even if other shared agents remain configured (data loss / unexpected behavior). Consider treating AGENTS.md as a shared resource: only delete it when no remaining configured agents map to it, or never auto-delete shared config files and instead just update the manifest (optionally prompting the user).

		AGENT_FILES = {
			"claude"   : "CLAUDE.md",
			"copilot"  : "AGENTS.md",
			"cursor"   : ".cursorrules",
			"codex"    : "AGENTS.md",
			"gemini"   : "GEMINI.md",
			"opencode" : "AGENTS.md"

[Copilot]

This bullet is a bit misleading: coldbox ai refresh will create/write the new AGENTS.md location, but it will not remove existing .github/copilot-instructions.md files. Consider rewording to explicitly state that old files must be removed manually if desired.

Suggested change

	- Existing `.github/copilot-instructions.md` files are not removed automatically; run `coldbox ai refresh` to write the updated location
	- Running `coldbox ai refresh` writes the new `AGENTS.md` location, but any existing `.github/copilot-instructions.md` files are not removed automatically and must be deleted manually if desired

[Copilot]

The "Supported Agents" list marks Copilot as using AGENTS.md (shared) but leaves Codex/OpenCode as just AGENTS.md. Since all three now share the same file, this line should mark Codex and OpenCode as shared as well (or rephrase to avoid inconsistency).

Suggested change

	- **Supported Agents**: Claude (`CLAUDE.md`), GitHub Copilot (`AGENTS.md`, shared), Cursor (`.cursorrules`), Codex (`AGENTS.md`), Gemini (`GEMINI.md`), OpenCode (`AGENTS.md`)
	- **Supported Agents**: Claude (`CLAUDE.md`), GitHub Copilot (`AGENTS.md`, shared), Cursor (`.cursorrules`), Codex (`AGENTS.md`, shared), Gemini (`GEMINI.md`), OpenCode (`AGENTS.md`, shared)

[Copilot]

This supported-agents list marks Copilot as using AGENTS.md (shared) but does not indicate that Codex and OpenCode also share AGENTS.md. Update the wording for accuracy/consistency (or phrase it as a single shared AGENTS.md used by multiple agents).

Suggested change

	**Supported Agents**: Claude (CLAUDE.md → AGENTS.md), GitHub Copilot (AGENTS.md, shared), Cursor (.cursorrules), Codex (AGENTS.md), Gemini (GEMINI.md), OpenCode (AGENTS.md)
	**Supported Agents**: Claude (CLAUDE.md → AGENTS.md), GitHub Copilot/Codex/OpenCode (shared `AGENTS.md`), Cursor (.cursorrules), Gemini (GEMINI.md)

[Copilot]

The help text says "Each agent creates its own configuration file", but Copilot (and also Codex/OpenCode) now share AGENTS.md. Update this wording to avoid implying one-file-per-agent (e.g., "Agent configuration files:" or explicitly note which agents share AGENTS.md).