chore(go): audit providers kimi grok qwen letta

Move Kimi, Grok, and Qwen onto managed_runtime.go and shell_command.go;
share the encoded and shell command builders and the quoted Windows
legacy parser with Droid; split managed_changes.go; dedupe Letta's hook
entry filtering and stop swallowing settings read errors.

Claude-Session: https://claude.ai/code/session_01Agoc9bRVE9KL7mmWtey9Vq

cmd/elydora/plugins/kimi_io.go

@@ -66,7 +66,7 @@ func resolveKimiContracts() ([]kimiContract, error) {
 	legacyHome := filepath.Join(home, ".kimi")
 	stable := stableKimiContract(filepath.Join(stableHome, "config.toml"))
 	legacy := legacyKimiContract(filepath.Join(legacyHome, "config.toml"))
-	if sameKimiPath(stable.configPath, legacy.configPath) {
+	if sameManagedPath(stable.configPath, legacy.configPath) {
 		return []kimiContract{stable}, nil
 	}