Inconsistent Copilot commands, naming, and feature availability across platforms

### Describe the feature or problem you'd like to solve

GitHub Copilot currently behaves differently across platforms and integrations, such as CLI, VS Code, and IDE/plugin-based environments. The same capability may have different command names, some commands exist only on certain platforms, and some features are available in one environment but missing or differently implemented in another. This inconsistency creates unnecessary confusion for users who work across multiple Copilot surfaces. It increases the learning curve, makes documentation harder to follow, and reduces confidence in adopting Copilot as a unified developer assistant.

### Proposed solution

# Inconsistent Copilot commands, naming, and feature availability across platforms

## Summary
GitHub Copilot currently behaves differently across platforms and integrations such as CLI, VS Code, and IDE/plugin-based environments. The same capability may have different command names, some commands exist only on certain platforms, and some features are available in one environment but missing or implemented differently in another.

This inconsistency creates confusion for users who work across multiple Copilot surfaces. It increases the learning curve, makes documentation harder to follow, and reduces confidence in Copilot as a unified developer assistant.

## Problem
Today, Copilot does not feel like a consistent product across platforms. In particular:

- Similar commands may have different names depending on the platform
- Some commands exist in one environment but not in another
- The same feature may behave differently across integrations
- Users cannot reliably transfer knowledge from one Copilot interface to another
- Documentation and onboarding become fragmented because platform-specific differences are not always obvious

## Why this matters
Many developers use Copilot in more than one environment during the same workflow. For example:

- Copilot in the CLI for terminal tasks
- Copilot in VS Code for coding
- Copilot in IDE/plugin integrations for project-specific workflows

When commands and features are not aligned, the experience feels disconnected. Users have to relearn the tool in each environment instead of building on the same mental model.

## Expected behavior
GitHub Copilot should provide a more unified cross-platform experience, including:

- Consistent command naming across platforms
- Aligned feature sets where technically possible
- Clear mapping when the same capability must be exposed differently
- Standardized terminology in UI and documentation
- A shared baseline of core commands and features across CLI, VS Code, and IDE/plugin integrations

## Actual behavior
Commands, naming, and features vary by platform. As a result, users may assume a feature is missing, renamed, or unsupported when switching contexts, even if it exists in another Copilot surface.

## Suggested improvement
Please consider introducing a synchronization/alignment effort across Copilot platforms:

1. Define a common set of core commands and capabilities
2. Standardize command names wherever possible
3. Provide an official compatibility matrix showing:
- Command name
- Equivalent command on other platforms
- Feature availability
- Known limitations
4. Use consistent terminology in documentation and product UI
5. Where exact parity is not possible, document platform-specific differences explicitly

## Example expectation
/fleet in CLI and /subAgents in VS code should have the same naming.

## Impact
This would improve:

- Usability
- Discoverability
- Onboarding
- Documentation quality
- Trust in Copilot as a unified product ecosystem

## Request
Please consider harmonizing Copilot commands and feature behavior across CLI, VS Code, and other IDE/plugin integrations, or at least provide a clear and official cross-platform mapping so users can move between environments without confusion.

### Example prompts or workflows

_No response_

### Additional context

_No response_

Comece comparando as superfícies de comandos da CLI, do VS Code e da IDE/plugin, usando /fleet e /subAgents como os exemplos concretos mencionados na issue. Defina o inventário comum de comandos e funcionalidades necessário para verificar a consistência dos nomes, a disponibilidade e as diferenças de plataforma documentadas.

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