Copilot CLI: ask_work_iq silently hangs due to EULA gate + auth tokens not persisting across MCP restarts

Description

When the WorkIQ MCP server is spawned by GitHub Copilot CLI (via the plugin marketplace config), two issues prevent ask_work_iq from working:

1. EULA gate causes silent hang. If accept_eula has not been called in the current MCP session, calling ask_work_iq hangs indefinitely with no error response. The Copilot CLI has no way to know it needs to call accept_eula first — the tool is listed alongside ask_work_iq in tools/list with no indication that it's a prerequisite.

2. Auth tokens are not cached across MCP server restarts. Each time the Copilot CLI spawns the MCP server process, a new browser sign-in prompt is triggered. When the CLI spawns the server as a background process, this prompt may not be visible to the user, causing the ask_work_iq call to hang or fail silently. Tokens obtained via workiq ask (interactive CLI) are not reused by workiq mcp (server mode).

Related Issues

• #87 — workiq does not cache identity (same root cause, VS Code context)
• #114 — Authentication as MCP Server in VS Code not working (same root cause, VS Code context)

Steps to Reproduce

1. Install WorkIQ via Copilot CLI plugin marketplace (/plugin install workiq@work-iq)
2. Restart Copilot CLI
3. Ask a question that triggers ask_work_iq (e.g., "What meetings do I have today?")
4. Observe: the tool call returns Tool 'ask_work_iq' does not exist or hangs

Manual MCP verification (proves the server works)

npx -y @microsoft/workiq mcp
# Send JSON-RPC initialize -> works
# Send tools/list -> returns accept_eula, ask_work_iq, get_debug_link
# Send accept_eula -> works
# Send ask_work_iq (after completing browser sign-in) -> works

Expected Behavior

• accept_eula state should persist across MCP server restarts (or EULA acceptance should be handled during plugin install)
• Auth tokens should be cached and reused between workiq ask (CLI) and workiq mcp (server) sessions
• If auth or EULA is required, ask_work_iq should return a clear error message instead of hanging silently

Environment

• WorkIQ version: 0.4.1
• Node.js: v24.13.0
• OS: Windows 11
• Client: GitHub Copilot CLI v1.0.41
• MCP config: npx -y @microsoft/workiq mcp (stdio transport)

Start by tracing the workiq mcp and workiq ask entry points, focusing on accept_eula, ask_work_iq, and authentication initialization across MCP restarts. Reproduce the Copilot CLI flow with npx -y @microsoft/workiq mcp; done means cached EULA and auth state are reused and missing prerequisites return clear errors instead of hanging.