refactor: remove unused GET /prompts/command/{command} endpoint (#24782)

The lookup-prompt-by-command endpoint's only frontend wrapper,
getPromptByCommand, is dead: nothing imports or calls it, the path is
referenced nowhere else, and the route handler has no internal caller
(slash-command resolution happens client-side from the loaded prompt
list). Removes the route handler, its section header, and the dead
wrapper.

The shared Prompts.get_prompt_by_command data-layer method is kept: it
is still used by create/update prompt validation (prompts.py:175, 275,
340). PromptAccessResponse and AccessGrants are untouched.

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/lib/apis/prompts/index.ts

@@ -226,40 +226,6 @@ export const getPromptList = async (token: string = '') => {
 	return res;
 };
 
-export const getPromptByCommand = async (token: string, command: string) => {
-	let error = null;
-
-	command = command.charAt(0) === '/' ? command.slice(1) : command;
-
-	const res = await fetch(`${WEBUI_API_BASE_URL}/prompts/command/${command}`, {
-		method: 'GET',
-		headers: {
-			Accept: 'application/json',
-			'Content-Type': 'application/json',
-			authorization: `Bearer ${token}`
-		}
-	})
-		.then(async (res) => {
-			if (!res.ok) throw await res.json();
-			return res.json();
-		})
-		.then((json) => {
-			return json;
-		})
-		.catch((err) => {
-			error = err.detail;
-
-			console.error(err);
-			return null;
-		});
-
-	if (error) {
-		throw error;
-	}
-
-	return res;
-};
-
 export const getPromptById = async (token: string, promptId: string) => {
 	let error = null;