chore(release): bump version to 0.1.2

Patch release — Tailscale auth documentation and spec alignment:
- Full inline docs for auth stack (AuthContext, middleware, error mapping)
- FEAT-012 updated: V1 ACs checked off, implementation status table, tag aliases
- ADR-005 accepted: crate choice documented, operational notes expanded
- axon-core Role::from_tag: add tag:admin, tag:axon-agent, tag:write, tag:read aliases
- Microsite: new /docs/concepts/authentication page, concepts card, CLI flag table

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: easel

Cargo.toml

@@ -16,7 +16,7 @@ members = [
 resolver = "2"
 
 [workspace.package]
-version = "0.1.1"
+version = "0.1.2"
 edition = "2021"
 license = "MIT OR Apache-2.0"
 repository = "https://github.com/easylabz/axon"