feat(cli): add MCP management subcommand with add/list/remove commands

Introduce `McpCommand` enum and handlers in `owlen-cli` to manage MCP server registrations, including adding, listing, and removing servers across configuration scopes. Add scoped configuration support (`ScopedMcpServer`, `McpConfigScope`) and OAuth token handling in core config, alongside runtime refresh of MCP servers. Implement toast notifications in the TUI (`render_toasts`, `Toast`, `ToastLevel`) and integrate async handling for session events. Update config loading, validation, and schema versioning to accommodate new MCP scopes and resources. Add `httpmock` as a dev dependency for testing.

crates/owlen-tui/src/commands/mod.rs

@@ -235,7 +235,7 @@ pub fn match_score(candidate: &str, query: &str) -> Option<(usize, usize)> {
     if candidate_normalized == query_normalized {
         Some((0, candidate.len()))
     } else if candidate_normalized.starts_with(&query_normalized) {
-        Some((1, candidate.len()))
+        Some((1, 0))
     } else if let Some(pos) = candidate_normalized.find(&query_normalized) {
         Some((2, pos))
     } else if is_subsequence(&candidate_normalized, &query_normalized) {