cli: proper clap subcommands for daemon + expanded help

Convert daemon from hand-rolled string dispatch to proper clap
Subcommand enum with typed args. Add custom top-level help that
expands nested subcommands (same pattern as bcachefs-tools), so
`poc-memory --help` shows full paths like `agent daemon run`.

poc-memory/src/main.rs

@@ -408,15 +408,42 @@ enum GraphCmd {
     },
 }
 
+#[derive(Subcommand)]
+enum DaemonCmd {
+    /// Start the daemon (default)
+    Start,
+    /// Show daemon status
+    Status,
+    /// Show daemon log
+    Log {
+        /// Job name to filter by
+        job: Option<String>,
+        /// Number of lines to show
+        #[arg(long, default_value_t = 20)]
+        lines: usize,
+    },
+    /// Install systemd service
+    Install,
+    /// Trigger consolidation via daemon
+    Consolidate,
+    /// Run an agent via the daemon
+    Run {
+        /// Agent name (e.g. organize, replay, linker)
+        #[arg(default_value = "replay")]
+        agent: String,
+        /// Batch size
+        #[arg(default_value_t = 1)]
+        count: usize,
+    },
+    /// Interactive TUI
+    Tui,
+}
+
 #[derive(Subcommand)]
 enum AgentCmd {
     /// Background job daemon
-    Daemon {
-        /// Subcommand: status, log, install
-        sub: Option<String>,
-        /// Additional arguments
-        args: Vec<String>,
-    },
+    #[command(subcommand)]
+    Daemon(DaemonCmd),
     /// Run knowledge agents to convergence
     #[command(name = "knowledge-loop")]
     KnowledgeLoop {
@@ -596,7 +623,52 @@ enum DigestLevel {
     Auto,
 }
 
+/// Print help with subcommands expanded to show nested commands.
+fn print_help() {
+    use clap::CommandFactory;
+    let cmd = Cli::command();
+
+    println!("poc-memory - graph-structured memory store");
+    println!("usage: poc-memory <command> [<args>]\n");
+
+    for sub in cmd.get_subcommands() {
+        if sub.get_name() == "help" { continue }
+        let children: Vec<_> = sub.get_subcommands()
+            .filter(|c| c.get_name() != "help")
+            .collect();
+        if !children.is_empty() {
+            for child in &children {
+                let about = child.get_about().map(|s| s.to_string()).unwrap_or_default();
+                let full = format!("{} {}", sub.get_name(), child.get_name());
+                // Recurse one more level for daemon subcommands etc.
+                let grandchildren: Vec<_> = child.get_subcommands()
+                    .filter(|c| c.get_name() != "help")
+                    .collect();
+                if !grandchildren.is_empty() {
+                    for gc in grandchildren {
+                        let gc_about = gc.get_about().map(|s| s.to_string()).unwrap_or_default();
+                        let gc_full = format!("{} {}", full, gc.get_name());
+                        println!("  {:<34}{gc_about}", gc_full);
+                    }
+                } else {
+                    println!("  {:<34}{about}", full);
+                }
+            }
+        } else {
+            let about = sub.get_about().map(|s| s.to_string()).unwrap_or_default();
+            println!("  {:<34}{about}", sub.get_name());
+        }
+    }
+}
+
 fn main() {
+    // Handle --help ourselves for expanded subcommand display
+    let args: Vec<String> = std::env::args().collect();
+    if args.len() <= 1 || args.iter().any(|a| a == "--help" || a == "-h") && args.len() == 2 {
+        print_help();
+        return;
+    }
+
     let cli = Cli::parse();
 
     let result = match cli.command {
@@ -660,7 +732,7 @@ fn main() {
 
         // Agent
         Command::Agent(sub) => match sub {
-            AgentCmd::Daemon { sub, args } => cmd_daemon(sub.as_deref(), &args),
+            AgentCmd::Daemon(sub) => cmd_daemon(sub),
             AgentCmd::KnowledgeLoop { max_cycles, batch_size, window, max_depth }
                 => cmd_knowledge_loop(max_cycles, batch_size, window, max_depth),
             AgentCmd::ConsolidateBatch { count, auto, agent }
@@ -2681,33 +2753,15 @@ fn cmd_lookups(date: Option<&str>) -> Result<(), String> {
     Ok(())
 }
 
-fn cmd_daemon(sub: Option<&str>, args: &[String]) -> Result<(), String> {
+fn cmd_daemon(sub: DaemonCmd) -> Result<(), String> {
     match sub {
-        None => daemon::run_daemon(),
-        Some("status") => daemon::show_status(),
-        Some("log") => {
-            let (job, lines) = match args.first() {
-                None => (None, 20),
-                Some(s) => {
-                    if let Ok(n) = s.parse::<usize>() {
-                        (None, n)
-                    } else {
-                        let n = args.get(1).and_then(|s| s.parse().ok()).unwrap_or(20);
-                        (Some(s.as_str()), n)
-                    }
-                }
-            };
-            daemon::show_log(job, lines)
-        }
-        Some("install") => daemon::install_service(),
-        Some("consolidate") => daemon::rpc_consolidate(),
-        Some("run-agent") | Some("run") => {
-            let agent = args.first().map(|s| s.as_str()).unwrap_or("replay");
-            let count: usize = args.get(1).and_then(|s| s.parse().ok()).unwrap_or(1);
-            daemon::rpc_run_agent(agent, count)
-        }
-        Some("tui") => tui::run_tui(),
-        Some(other) => Err(format!("unknown daemon subcommand: {}", other)),
+        DaemonCmd::Start => daemon::run_daemon(),
+        DaemonCmd::Status => daemon::show_status(),
+        DaemonCmd::Log { job, lines } => daemon::show_log(job.as_deref(), lines),
+        DaemonCmd::Install => daemon::install_service(),
+        DaemonCmd::Consolidate => daemon::rpc_consolidate(),
+        DaemonCmd::Run { agent, count } => daemon::rpc_run_agent(&agent, count),
+        DaemonCmd::Tui => tui::run_tui(),
     }
 }