Add Wiki support and database creation to the TUI

[humandebri]

Summary

• Add Wiki database browsing to the TUI with dedicated database list, browser, and diagnostic states.
• Add a + Create database action row and wire it to WikiClient::create_database() with refresh and selection recovery after success.
• Bundle the Wiki wasm/candid, update CLI/TUI docs, and expand provider/runtime/render tests for Wiki flows.

Testing

• cargo test wiki --lib
• cargo test -p tui-kit-render wiki
• cargo test -p tui-kit-runtime wiki_create_action
• cargo test -p tui-kit-runtime wiki_database_list_move_next_reaches_create_action_row
• cargo test -p tui-kit-host select_list_item_effect_can_select_wiki_create_action_row