Refreshes the README so the first screen and security story match Radar’s current product positioning: a local-first Kubernetes UI that runs as a single binary, requires no account or agents, and keeps cluster data local.

What changed

• Standardizes the hero around “The missing open-source Kubernetes UI” and a shorter trust line: single binary, no account required, free forever.
• Adds a collapsible table of contents so the long README is easier to scan.
• Reworks the first-screen feature line around topology, resources, GitOps, traffic, audit, and MCP context for AI agents.
• Reworks the Why Radar section with concrete performance language, private-by-design / airgapped-friendly messaging, and a validated scale claim for tens of thousands of pods.
• Clarifies installation and usage details: kubectl radar is universal; quick install, PowerShell, Homebrew, and Scoop also set up radar; Krew and direct downloads use kubectl radar unless users add a symlink.
• Adds a README Security section and aligns SECURITY.md around the core trust promise: no cluster telemetry, no upload of manifests, logs, events, metrics, or resource data to Skyhook, and no account, agent, or cloud backend requirement.
• Uses “AI agents” consistently across README, MCP docs, GitOps docs, and the MCP setup dialog.
• Keeps roadmap detail out of the README by linking RBAC follow-ups to RBAC visibility: considered follow-ups #1090; removes the MCP beta label and adds Discussions/community pointers.

Testing

• git diff --check origin/main...HEAD
• Docs/copy-only change; no runtime tests or visual test run.