feat(source2): lock dark mode, sans-serif typography, and all recent updates

docs/vibe-coding/antigravity-ide.md

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+# Antigravity IDE
+
+Same config model as the [Antigravity CLI](antigravity-cli.md) — the IDE and CLI
+share the same agent harness.
+
+- Root-level `AGENTS.md` is read automatically before any agent starts work in the
+  workspace; this kit's `AGENTS.md` needs no changes.
+- Global, cross-project preferences: `~/.gemini/GEMINI.md`.
+- Project-only, non-shared rules: `.agents/rules/` in the workspace.
+- Skills (directory-based, loaded on demand) live under `.agents/skills/` if you want
+  to promote a `SKILLS.md` role into a dedicated loadable package.
+- To confirm the IDE picked up `AGENTS.md`, open the agent's context/inspector panel
+  and check the loaded-files list.