fix(gemini): implement native transactional hooks

cmd/elydora/plugins/gemini_io.go

@@ -0,0 +1,104 @@
+package plugins
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+)
+
+func geminiConfigurationDirectory() (string, error) {
+	configured := os.Getenv("GEMINI_CLI_HOME")
+	if configured == "" {
+		home, err := os.UserHomeDir()
+		if err != nil {
+			return "", fmt.Errorf("resolve home directory: %w", err)
+		}
+		configured = home
+	}
+	return filepath.Join(configured, ".gemini"), nil
+}
+
+func geminiSettingsPath() (string, error) {
+	directory, err := geminiConfigurationDirectory()
+	if err != nil {
+		return "", err
+	}
+	return filepath.Join(directory, geminiConfigFile), nil
+}
+
+func readGeminiDocument() (*geminiDocument, error) {
+	filePath, err := geminiSettingsPath()
+	if err != nil {
+		return nil, err
+	}
+	if _, err := managedPhysicalDirectoryExists(
+		filepath.Dir(filePath),
+		"Gemini CLI configuration directory",
+	); err != nil {
+		return nil, err
+	}
+	snapshot, err := readManagedFile(
+		filePath,
+		"Gemini CLI user settings",
+		maxManagedSourceBytes,
+	)
+	if err != nil {
+		return nil, err
+	}
+	if snapshot == nil {
+		return createGeminiDocument(filePath)
+	}
+	return parseGeminiDocument(true, filePath, snapshot.contents)
+}
+
+func prepareRenderedGeminiChange(
+	rendered *geminiRenderedDocument,
+) (*fileChange, error) {
+	if rendered == nil || !rendered.changed {
+		return nil, nil
+	}
+	return prepareSourceChange(
+		rendered.document.filePath,
+		"Gemini CLI user settings",
+		rendered.document.raw,
+		rendered.document.exists,
+		rendered.next,
+		0600,
+		rendered.remove,
+	)
+}
+
+func writeGeminiChanges(
+	changes []*fileChange,
+	label string,
+	rename renameFunc,
+	runtimeRoot string,
+	agentDirectory string,
+	settingsDirectory string,
+) error {
+	hasChanges := false
+	for _, change := range changes {
+		if change != nil {
+			hasChanges = true
+			break
+		}
+	}
+	if !hasChanges {
+		return nil
+	}
+	if agentDirectory != "" {
+		if err := EnsurePrivateDirectory(runtimeRoot); err != nil {
+			return err
+		}
+		if err := EnsurePrivateDirectory(agentDirectory); err != nil {
+			return err
+		}
+	}
+	if err := ensureManagedDirectory(
+		settingsDirectory,
+		"Gemini CLI configuration directory",
+	); err != nil {
+		return err
+	}
+	return writeChanges(changes, label, rename)
+}