toggle_element silently closes all panels when given an unrecognised element name

[ooloth]

Why

toggle_element iterates over layouts_index_by_element to find a matching element, but if the given name is not a key, the loop closes every panel and opens none — a silent no-op failure that gives the developer no diagnostic.

Current state

lua/config/plugins/specs/nvim-dap.lua lines 39–63: local function toggle_element(element) — no assertion or early return checks that element is a recognised key in layouts_index_by_element before the loop runs. An unrecognised element name causes the loop to exhaust all entries, closing each panel, and the function returns silently.

Ideal state

• toggle_element asserts (via vim.notify with an error level, or an early return) that element is a recognised key before entering the loop.
• An unrecognised element name produces a visible message instead of silently closing all panels.

Starting points

• lua/config/plugins/specs/nvim-dap.lua — lines 39–63, the toggle_element function and the layouts_index_by_element table it reads

QA plan

1. Call toggle_element("nonexistent") — expect a notification or error message naming the bad input, and no panels are closed.
2. Call toggle_element with a valid element name — expect normal toggle behaviour unchanged.

Done when

Passing an unrecognised element name to toggle_element produces a visible diagnostic instead of silently closing all open DAP UI panels.