Add AbortSignal support to API functions for request cancellation

Add optional signal?: AbortSignal parameter to all API GET functions so they can be
cancelled when components unmount. This prevents state-update warnings and wasted
resources.

Changes:
- frontend/src/api/history.ts: fetchHistory, fetchIpHistory
- frontend/src/api/map.ts: fetchBansByCountry
- frontend/src/api/jails.ts: fetchJails, fetchActiveBans
- frontend/src/api/config.ts: fetchJailConfig, fetchInactiveJails, fetchJailConfigFiles,
  fetchFilterFiles (threads signal through fetchFilters), fetchFilterFile, fetchActionFiles,
  fetchActionFile
- frontend/src/api/blocklist.ts: fetchImportLog, previewBlocklist

Updated all calling hooks to pass the abort signal from their controllers:
- useHistory, useIpHistory
- useMapData
- useActiveBans
- useJails
- useConfigActiveStatus (fetchJails and fetchJailConfigs)
- useJailAdmin (fetchInactiveJails)
- useJailConfigDetail (fetchJailConfig)
- useImportLog (fetchImportLog)
- useBlocklists (previewBlocklist with AbortController)

Updated Docs/Web-Development.md to document the convention.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Docs/Web-Development.md

@@ -76,14 +76,16 @@ import type { Ban } from "../types/ban";
 - Use a **central API client** (e.g., a thin wrapper around `fetch` or `axios`) that returns typed data — individual components never call `fetch` directly.
 - Validate or assert the response structure at the boundary when dealing with untrusted data; for critical flows, consider a runtime validation library (e.g., `zod`).
 - API endpoint paths are **constants** defined in a single file (`api/endpoints.ts`) — never hard-code URLs in components.
+- **All API functions that perform a `GET` request must accept an optional `signal?: AbortSignal` parameter and forward it to the HTTP client.** This enables hooks to cancel in-flight requests when components unmount, preventing silent state-update errors and wasted resources. When an API function calls another internal API function, thread the signal through to the underlying call.
 
 ```ts
 // api/client.ts
 const BASE_URL = import.meta.env.VITE_API_URL ?? "/api";
 
-async function get<T>(path: string): Promise<T> {
+async function get<T>(path: string, signal?: AbortSignal): Promise<T> {
   const response: Response = await fetch(`${BASE_URL}${path}`, {
     credentials: "include",
+    signal,
   });
   if (!response.ok) {
     throw new ApiError(response.status, await response.text());
@@ -99,11 +101,19 @@ export const api = { get, post, put, del } as const;
 import type { BanListResponse } from "../types/ban";
 import { api } from "./client";
 
-export async function fetchBans(hours: number): Promise<BanListResponse> {
-  return api.get<BanListResponse>(`/bans?hours=${hours}`);
+export async function fetchBans(hours: number, signal?: AbortSignal): Promise<BanListResponse> {
+  return api.get<BanListResponse>(`/bans?hours=${hours}`, signal);
 }
 ```
 
+```ts
+// hooks/useBans.ts
+const ctrl = new AbortController();
+fetchBans(24, ctrl.signal)  // Pass the signal to enable cancellation on unmount
+  .then(resp => { /* ... */ })
+  .catch(err => { /* ... */ });
+```
+
 ---
 
 ## 4. Code Organization