Interface switching should not destroy conversation context

Switching between views/interfaces in Claude Code destroys conversation context. This breaks a fundamental UX convention held by virtually every other application ever built: interface state and data state are separate concerns.

In Slack, switching channels doesn't delete your DMs. In a browser, switching tabs doesn't erase your history. In VS Code itself, switching files doesn't close your other files. Claude Code conflates "where you're looking" with "what exists" — and users shouldn't have to understand the underlying architecture to use the tool.

The fix is obvious: unified conversation history, filtered by context depending on which view you're in. The data doesn't change, the lens does. This is how every mature product handles it.

A concrete example that happened while filing this issue:

The gh CLI is installed and authenticated on this machine. The Claude Code session running inside VS Code knew that — it operates within the user's full shell environment. The Claude.ai app session, used to draft this issue, had no idea gh existed and failed to post it.

Same machine. Same user. Same tools installed. Completely blind to each other.

This isn't just about conversation history — it's a broader environment isolation problem. Two Claude Code surfaces running simultaneously on the same machine share no shell environment, no installed tools, no credentials, no PATH. Every session starts from scratch.

The result: users cannot build a coherent workflow across surfaces. The tool that knows your codebase doesn't know your shell. The tool that knows your shell doesn't know your conversation. You are constantly context-switching between isolated islands, manually carrying state in your head that the tool could trivially share.

The fix isn't complicated in principle: a shared environment layer that all Claude Code surfaces can read from — shell context, installed tools, active credentials. The conversation window can remain isolated. The environment should not be.

This isn't a v1 rough edge — it's a design principle being violated at scale. Users shouldn't feel the architecture.