feat(go): durable transaction engine and Kiro IDE 1.0 adapter

Split the monolithic transaction into focused modules: append-only
crash-recoverable journal under ~/.elydora/transactions with owner
tokens and per-transaction namespaces, staged atomic publication
(stage .pending, fsync, rename, fsync), platform-specific atomic
replacement (MoveFileEx, renameat2, renamex_np), private-directory
hardening per OS, lock-guarded recovery, and workspace cleanup that
removes only transaction-created empty directories.

Add the Kiro IDE 1.0 plugin: strict v1 hook schema with one enabled
PreToolUse guard and PostToolUse audit pair bound to the active
workspace, agent-to-workspace identity binding in runtime config, and
exact migration of the legacy elydora-audit.kiro.hook contract.

Gates: go test ./... and -race pass, go vet clean, govulncheck reports
zero reachable vulnerabilities, git diff --check clean.

cmd/elydora/plugins/runtime_files_test.go

@@ -12,6 +12,7 @@ import (
 func setRuntimeFilesTestHome(t *testing.T) string {
 	t.Helper()
 	home := t.TempDir()
+	preparePrivateTransactionTestDirectory(t, home)
 	t.Setenv("HOME", home)
 	t.Setenv("USERPROFILE", home)
 	return home