init: install hooks + scaffold config; load-context: inline instructions

poc-memory init now:
- Creates the data directory
- Installs the memory-search hook into Claude settings.json
- Scaffolds a starter config.jsonl if none exists

load-context now prints a command reference block at the top so the
AI assistant learns how to use the memory system from the memory
system itself — no CLAUDE.md dependency needed.

Also extract install_hook() as a public function so both init and
daemon install can use it.

Co-Authored-By: ProofOfConcept <poc@bcachefs.org>

src/daemon.rs

@@ -646,13 +646,18 @@ WantedBy=default.target
     eprintln!("Service enabled and started");
 
     // Install memory-search hook into Claude settings
-    install_hook(&home, &exe)?;
+    install_hook()?;
 
     Ok(())
 }
 
-fn install_hook(home: &str, exe: &Path) -> Result<(), String> {
-    let settings_path = PathBuf::from(home).join(".claude/settings.json");
+/// Install the memory-search hook into Claude Code settings.json.
+/// Public so `poc-memory init` can call it too.
+pub fn install_hook() -> Result<(), String> {
+    let home = std::env::var("HOME").map_err(|e| format!("HOME: {}", e))?;
+    let exe = std::env::current_exe()
+        .map_err(|e| format!("current_exe: {}", e))?;
+    let settings_path = PathBuf::from(&home).join(".claude/settings.json");
     let hook_binary = exe.with_file_name("memory-search");
 
     if !hook_binary.exists() {