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/managed_files.go

@@ -13,6 +13,7 @@ type managedFileSnapshot struct {
 	contents []byte
 	info     os.FileInfo
 	mode     os.FileMode
+	identity string
 }
 
 func readManagedFile(
@@ -51,6 +52,13 @@ func readManagedFile(
 			file.Close(),
 		)
 	}
+	identity, identityErr := transactionFileIdentity(file, after)
+	if identityErr != nil {
+		return nil, errors.Join(
+			fmt.Errorf("identify %s at %s: %w", label, filePath, identityErr),
+			file.Close(),
+		)
+	}
 	raw, readErr := io.ReadAll(io.LimitReader(file, maximumBytes+1))
 	closeErr := file.Close()
 	if readErr != nil || closeErr != nil {
@@ -70,6 +78,7 @@ func readManagedFile(
 		contents: raw,
 		info:     after,
 		mode:     after.Mode().Perm(),
+		identity: identity,
 	}, nil
 }