v0.5.1 — branding + readme refresh

v0.5.1 — branding + readme refresh

Small patch release. No API changes — docs, logo, and publish-script housekeeping.

What's Changed

• Logo + README pass. New assets/logo.png, themed mdBook header, and a unified intro across the workspace READMEs. Per-crate READMEs (agentkit, agentkit-core, agentkit-http, agentkit-loop, agentkit-mcp, all provider crates) refreshed for the post-rmcp surface.
• Installation / session-persistence docs rewritten against the 0.5 API.
• Publish script picks up the new agentkit-tools-derive crate so cargo publish runs cover it.

No code changes; safe drop-in upgrade from 0.5.0.

Commits

• chore: new crate to publish script (a15bf3c)
• docs: logo + update readmes (1d31b11)
• chore(version): 0.5.1 (512a6a2)

Full Changelog: v0.5.0...v0.5.1