chore: add sproutclaw git workflow and track local extensions

Document main/upstream-sync/feature branch strategy, add sync/push
scripts, track .pi/agent extensions and webui in git, and disable
startup changelog via showChangelogOnStartup.

Co-authored-by: Cursor <cursoragent@cursor.com>

scripts/push-sproutclaw.sh

@@ -0,0 +1,32 @@
+#!/usr/bin/env bash
+# Push main (and upstream-sync if present) to GitHub and Gitea.
+set -euo pipefail
+
+ROOT="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
+cd "$ROOT"
+
+export GIT_HTTP_VERSION="${GIT_HTTP_VERSION:-1.1}"
+
+BRANCH="$(git branch --show-current)"
+if [[ "$BRANCH" != "main" ]]; then
+	echo "Checkout main before pushing (current: $BRANCH)" >&2
+	exit 1
+fi
+
+echo "==> Push main -> origin (GitHub)"
+git push origin main
+
+if git show-ref --verify --quiet refs/heads/upstream-sync; then
+	echo "==> Push upstream-sync -> origin"
+	git push origin upstream-sync
+fi
+
+if git remote get-url gitea &>/dev/null; then
+	echo "==> Push main -> gitea"
+	git push gitea main
+	if git show-ref --verify --quiet refs/heads/upstream-sync; then
+		git push gitea upstream-sync
+	fi
+fi
+
+echo "Done."