chore: bump version to 0.5.0

The v0.5.0 release was published but the PyPI publish workflow failed
because pyproject.toml still had version 0.4.13. This commit aligns
the version to match the release tag so the publish workflow succeeds.

Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>

Author: timeleft--

pyproject.toml

@@ -1,6 +1,6 @@
 [project]
 name = "fava-trails"
-version = "0.4.13"
+version = "0.5.0"
 description = "FAVA Trails 🫛👣 — Federated Agents Versioned Audit Trail. VCS-backed memory for AI agents via MCP."
 readme = "README.md"
 requires-python = ">=3.11"