Pause gate, /demo-status endpoint, and Case.dev integration docs
kveton added a public `/demo-status` endpoint and a frontend landing page that activates when `MIKE_DEMO_CASE_API_KEY` is set but `MIKE_DEMO_MODE` is off -- a clean way to pause the hosted demo without taking the whole app down. This PR also doubled as the README for the fork's Case.dev integration, laying out the full primitive map and BYOK escape hatches.
The /demo-status endpoint (GET) returns four fields: enabled, hosted_demo_configured, disabled_landing, and budget_usd. The frontend reads it and swaps in a static paused-demo page when disabled_landing is true. The gate is inert on any fork or local install that doesn't have MIKE_DEMO_CASE_API_KEY configured, so merging this doesn't affect non-hosted deployments.
A second commit added an extensive Case.dev integration breakdown to the README. The "Choose Your Integration Depth" section lists five modes from full Case.dev through a Case-free fork, and the primitive map table documents every Case.dev service by wiring status (live, future, or not used). The adapter seams are named directly: caseClient.ts, storage.ts, llm/index.ts, chatTools.ts, caseMatters.ts, and the routes layer.
Also in this PR: app metadata was refreshed for launch (title updated to "MikeOSS Case.dev Demo", description updated), and the .env.example got a comment documenting the MIKE_DEMO_GLOBAL_BUDGET_USD emergency cap for abuse control.
Spotted something wrong? Or know the PR text has fresher detail than the writeup above?