docs: prioritize server self-hosting

[Uarmagan]

Summary

This PR removes the local Docker quickstart from the self-hosting docs and makes server hosting the primary newcomer path.

The docs now frame self-hosting as running Compass on a server you control, with the server guide as the first place to start. Local use is still covered, but it is described as the normal Bun/manual setup rather than a separate local Docker self-host option.

What changed

• Deleted docs/self-hosting/local-quickstart.md.
• Updated the self-hosting overview to point newcomers to the server guide first.
• Updated README and self-host runtime docs so they no longer advertise local Docker as the recommended self-host path.
• Reworded Google Calendar and troubleshooting docs so localhost guidance applies to local development or server-internal checks, not a promoted local self-host install.
• Kept backup and installer references focused on the server self-host stack.

Why

The previous docs made localhost Docker sound like the recommended path for new self-hosters. That created an extra supported mode alongside normal Bun-based local use and VPS hosting. This narrows the public self-hosting story: newcomers who want to self-host should start with the server guide, while people who want to run Compass locally can use the existing Bun flow.

Verification

• rg -n "local-quickstart|Local quickstart" README.md docs self-host
• sh -n self-host/install.sh
• sh -n self-host/compass
• git diff --check
• bun test self-host/docker-compose.test.ts
• bun run lint completed with existing repo warnings unrelated to this docs change.