Add backup protection to all user file writes

Extract backup_config_file() from config_writer into a shared
utils::backup::backup_file() utility that handles any file extension.
Add backup calls before every fs::write to user-owned files across
all 12 writer modules:

- hook_writer (settings.json, settings.local.json)
- claude_settings (settings.json, settings.local.json)
- permission_writer (settings.json)
- spinner_verb_writer (settings.json)
- keybindings_writer (keybindings.json)
- memory_writer (CLAUDE.md, CLAUDE.local.md)
- agent_memory_writer (agent memory .md files)
- skill_writer (SKILL.md, OpenCode agent .md)
- subagent_writer (agent .md, OpenCode agent .md)
- rule_writer (rule .md files)
- command_writer (command .md, OpenCode command .md)
- config_writer (now uses shared utility)

Every user file now gets a .bak copy before modification, ensuring
no data loss on first run or subsequent syncs.

Author: tylergraydev

src-tauri/Cargo.lock

@@ -108,6 +108,7 @@ pub fn write_agent_memory(
         std::fs::create_dir_all(parent)?;
     }
 
+    crate::utils::backup::backup_file(&path)?;
     std::fs::write(&path, content)?;
     read_agent_memory(agent_name, scope, project_path)
 }

src-tauri/src/services/agent_memory_writer.rs

@@ -111,6 +111,7 @@ fn write_settings_file(path: &Path, settings: &Value) -> Result<()> {
     if let Some(parent) = path.parent() {
         std::fs::create_dir_all(parent)?;
     }
+    crate::utils::backup::backup_file(path)?;
     let content = serde_json::to_string_pretty(settings)?;
     std::fs::write(path, content)?;
     Ok(())

src-tauri/src/services/claude_settings.rs

@@ -52,6 +52,7 @@ pub fn write_command_file(base_path: &Path, command: &Command) -> Result<()> {
     std::fs::create_dir_all(&commands_dir)?;
 
     let file_path = commands_dir.join(format!("{}.md", command.name));
+    crate::utils::backup::backup_file(&file_path)?;
     let content = generate_command_markdown(command);
     std::fs::write(file_path, content)?;
 
@@ -146,6 +147,7 @@ pub fn write_command_file_opencode(base_path: &Path, command: &Command) -> Resul
     std::fs::create_dir_all(&command_dir)?;
 
     let file_path = command_dir.join(format!("{}.md", command.name));
+    crate::utils::backup::backup_file(&file_path)?;
     let content = generate_command_markdown_opencode(command);
     std::fs::write(file_path, content)?;
 

src-tauri/src/services/command_writer.rs

@@ -3,23 +3,7 @@ use anyhow::Result;
 use serde_json::{json, Map, Value};
 use std::path::Path;
 
-/// Create a backup of the config file before modifying it
-fn backup_config_file(path: &Path) -> Result<()> {
-    if !path.exists() {
-        return Ok(());
-    }
-
-    let backup_path = path.with_extension("json.bak");
-    std::fs::copy(path, &backup_path).map_err(|e| {
-        anyhow::anyhow!(
-            "Failed to create backup of {} before writing: {}",
-            path.display(),
-            e
-        )
-    })?;
-
-    Ok(())
-}
+use crate::utils::backup::backup_file as backup_config_file;
 
 type McpTuple = (
     String,         // name

src-tauri/src/services/config_writer.rs

@@ -129,6 +129,8 @@ fn write_settings_file(path: &Path, settings: &Value) -> Result<()> {
         std::fs::create_dir_all(parent)?;
     }
 
+    crate::utils::backup::backup_file(path)?;
+
     let content = serde_json::to_string_pretty(settings)?;
     std::fs::write(path, content)?;
     Ok(())

src-tauri/src/services/hook_writer.rs

@@ -77,6 +77,7 @@ pub fn write_keybindings_to_path(path: &Path, kb: &KeybindingsFile) -> Result<()
             .collect(),
     };
 
+    crate::utils::backup::backup_file(path)?;
     let content = serde_json::to_string_pretty(&filtered)?;
     std::fs::write(path, content)?;
     Ok(())

src-tauri/src/services/keybindings_writer.rs

@@ -157,6 +157,7 @@ pub fn write_memory_file(
         std::fs::create_dir_all(parent)?;
     }
 
+    crate::utils::backup::backup_file(&path)?;
     std::fs::write(&path, content)?;
 
     // Read back the file info to return updated metadata

src-tauri/src/services/memory_writer.rs

@@ -49,6 +49,7 @@ fn write_settings_file(path: &Path, settings: &Value) -> Result<()> {
     if let Some(parent) = path.parent() {
         std::fs::create_dir_all(parent)?;
     }
+    crate::utils::backup::backup_file(path)?;
     let content = serde_json::to_string_pretty(settings)?;
     std::fs::write(path, content)?;
     Ok(())

src-tauri/src/services/permission_writer.rs

@@ -30,6 +30,7 @@ pub fn write_rule_file(base_path: &Path, rule: &Rule) -> Result<()> {
     std::fs::create_dir_all(&rules_dir)?;
 
     let file_path = rules_dir.join(format!("{}.md", rule.name));
+    crate::utils::backup::backup_file(&file_path)?;
     let content = generate_rule_markdown(rule);
     std::fs::write(file_path, content)?;