feat: BIP-39 master seed for unified key derivation

Replace fragmented random key generation with a single 24-word BIP-39
mnemonic that deterministically derives all node keys: Ed25519 (DID),
secp256k1 (Nostr/Bitcoin), BIP-84 xprv (Bitcoin Core), and LND aezeed
entropy. New onboarding flow: seed generate → word verification → identity
naming. Restore path enabled via 24-word entry. Includes seed RPC handlers,
mock backend support, LND/Bitcoin Core wallet-from-seed integration, and
UI polish across settings and discover views.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

core/archipelago/src/container/data_manager.rs

@@ -69,7 +69,6 @@ impl DevDataManager {
 #[cfg(test)]
 mod tests {
     use super::*;
-    use std::path::PathBuf;
 
     #[tokio::test]
     async fn test_map_volume_path() {

core/archipelago/src/container/mock_podman.rs

@@ -8,6 +8,7 @@ use std::sync::{Arc, Mutex, atomic::{AtomicBool, AtomicU32, Ordering}};
 
 /// Container state matching podman's real states.
 #[derive(Debug, Clone, PartialEq)]
+#[allow(dead_code)]
 pub enum MockContainerState {
     Created,
     Running,
@@ -28,6 +29,7 @@ impl MockContainerState {
 
 /// A simulated container.
 #[derive(Debug, Clone)]
+#[allow(dead_code)]
 pub struct MockContainer {
     pub name: String,
     pub image: String,
@@ -36,6 +38,7 @@ pub struct MockContainer {
 }
 
 /// Mock podman runtime for testing orchestration logic without real containers.
+#[allow(dead_code)]
 pub struct MockPodman {
     containers: Arc<Mutex<HashMap<String, MockContainer>>>,
     /// When true, `podman pull` will fail (simulates registry down).
@@ -50,6 +53,7 @@ pub struct MockPodman {
     images: Arc<Mutex<Vec<String>>>,
 }
 
+#[allow(dead_code)]
 impl MockPodman {
     pub fn new() -> Self {
         Self {