Refocus extension as MCP control plane instead of CLI GUI

[SebTardif]

Problem

The extension currently provides 6 Quick Action commands that duplicate VS Code built-in features (find-replace, file creation, search) with more friction. The real value of Patchloom is its MCP server that AI agents call, not a command palette GUI for humans.

After the initial 3-minute setup (binary + AGENTS.md + MCP config), the extension goes dormant. Users have no visibility into whether MCP is working or what the agent is doing through Patchloom.

Goal

Refocus the extension as the MCP server control plane: make MCP readiness the primary signal, add server health verification, and give users visibility into MCP configuration per editor.

Implementation Plan

Phase 1: MCP-aware status bar and diagnostics

• Status bar shows MCP state: Display $(plug) Patchloom MCP when MCP is configured, $(warning) Patchloom when binary is missing or MCP is not configured. The status bar is the most visible surface and should communicate what matters most.
• Enhanced status details with per-editor MCP breakdown: Instead of a single MCP config: present/missing, show which editors have MCP configured (VS Code, Cursor, Windsurf) individually. This helps users understand their exact setup state.
• Add "Verify MCP Server" command: New command Patchloom: Verify MCP Server that spawns patchloom mcp-server, sends a JSON-RPC initialize request, validates the response, and reports success/failure. This lets users confirm MCP actually works before relying on it.
• Setup Workspace runs the full flow without stopping: Currently the guided walkthrough stops after each step (binary, AGENTS.md, MCP) and requires re-running. Change it to walk through all steps in one invocation.

Phase 2: Tests and documentation

• Unit tests for all new behavior: Test MCP-aware status bar text, per-editor breakdown in details, verify command result handling.
• Update README: Reframe the extension around MCP/agent workflow instead of leading with Quick Actions. The setup flow and MCP control plane are the primary features.

Out of scope

• Removing Quick Actions (would be a breaking change for v0.0.x users, if any)
• MCP server process management (the AI client spawns and manages the server)
• MCP tool call observability (requires protocol-level integration with the client)

Why this matters

Patchloom targets developers using AI coding agents. The extension should help them get MCP working and stay confident it is working. A status bar that says "MCP Ready" is more useful than 6 commands they will never run manually.

[SebTardif]

Resolved by PR #94 (merged).