Fix DB lock error: clear message + instructions, fix passphrase reprompt

Storage:
- Detects sled lock contention, shows actionable error:
  "Database locked by another warzone process"
  with ps command to find the process and rm command to force unlock

TUI:
- Poll loop no longer calls load_seed() (was re-prompting passphrase)
- Seed passed from main.rs to run_tui to poll_loop
- Single passphrase prompt per app launch

Warnings fixed:
- Removed unused `Context` import in tui/app.rs
- Added #[allow(dead_code)] on validate_token (used when auth middleware wired)

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

warzone/crates/warzone-client/src/storage.rs

@@ -14,7 +14,25 @@ pub struct LocalDb {
 impl LocalDb {
     pub fn open() -> Result<Self> {
         let path = crate::keystore::data_dir().join("db");
-        let db = sled::open(&path).context("failed to open local database")?;
+        let db = match sled::open(&path) {
+            Ok(db) => db,
+            Err(e) => {
+                let err_str = e.to_string();
+                if err_str.contains("WouldBlock") || err_str.contains("lock") {
+                    eprintln!("Error: Database is locked by another warzone process.");
+                    eprintln!("  DB path: {}", path.display());
+                    eprintln!();
+                    eprintln!("  Check for running processes:");
+                    eprintln!("    ps aux | grep warzone-client");
+                    eprintln!();
+                    eprintln!("  To force unlock (if no other process is running):");
+                    eprintln!("    rm -rf {}", path.display());
+                    eprintln!("    (This deletes sessions — you'll need to re-establish them)");
+                    anyhow::bail!("database locked by another process");
+                }
+                return Err(e).context("failed to open local database");
+            }
+        };
         let sessions = db.open_tree("sessions")?;
         let pre_keys = db.open_tree("pre_keys")?;
         Ok(LocalDb {