chore: exclude data directories from gitbot-shared-context package

Add exclude field to Cargo.toml to prevent packaging data files
(findings/, learning/, dispatch/) which contain runtime data, not source code.

This allows gitbot-shared-context to be packaged and published to crates.io.

Generated by Mistral Vibe.
Co-Authored-By: Mistral Vibe <vibe@mistral.ai>

Author: hyperpolymath

shared-context/Cargo.toml

@@ -9,6 +9,7 @@ license = "MPL-2.0"
 repository = "https://github.com/hyperpolymath/gitbot-fleet"
 keywords = ["gitbot-fleet", "coordination", "context", "ci-cd"]
 categories = ["development-tools"]
+exclude = ["findings/", "learning/", "dispatch/"]
 
 [dependencies]
 # Serialization