fix(proxy): support bracketed IPv6 hosts in batch proxy URL parsing

The quick-add parser rejected every IPv6 proxy: the host group [^:]+
cannot match IPv6 literals (colons) and the pattern had no bracketed
form, so lines like socks5://[2001:db8::1]:1080 were reported invalid.

Add a bracketed-IPv6 host alternative and strip the brackets before
storing; the backend re-brackets via net.JoinHostPort when building the
proxy URL. Bare (unbracketed) IPv6 stays rejected because it is
ambiguous with host:port. Also add a regression test.

frontend/src/views/admin/ProxiesView.vue

@@ -1276,6 +1276,7 @@ const handleDataImported = () => {
 }
 
 // Parse proxy URL: protocol://user:pass@host:port or protocol://host:port
+// Host may be a domain, IPv4, or bracketed IPv6 ([2001:db8::1]).
 const parseProxyUrl = (
   line: string
 ): {
@@ -1288,20 +1289,26 @@ const parseProxyUrl = (
   const trimmed = line.trim()
   if (!trimmed) return null
 
-  // Regex to parse proxy URL (supports http, https, socks5, socks5h)
-  const regex = /^(https?|socks5h?):\/\/(?:([^:@]+):([^@]+)@)?([^:]+):(\d+)$/i
+  // Regex to parse proxy URL (supports http, https, socks5, socks5h).
+  // Host alternatives: [bracketed-IPv6] | hostname/IPv4 (colon-free, so the
+  // match stops before the final :port).
+  const regex =
+    /^(https?|socks5h?):\/\/(?:([^:@\[\]]+):([^@\[\]]+)@)?(\[[0-9a-f:.]+\]|[^:\[\]]+):(\d+)$/i
   const match = trimmed.match(regex)
 
   if (!match) return null
 
-  const [, protocol, username, password, host, port] = match
+  const [, protocol, username, password, rawHost, port] = match
   const portNum = parseInt(port, 10)
 
   if (portNum < 1 || portNum > 65535) return null
 
+  // Strip brackets from IPv6 literals; the backend re-brackets via net.JoinHostPort.
+  const host = rawHost.replace(/^\[|\]$/g, '').trim()
+
   return {
     protocol: protocol.toLowerCase() as ProxyProtocol,
-    host: host.trim(),
+    host,
     port: portNum,
     username: username?.trim() || '',
     password: password?.trim() || ''

frontend/src/views/admin/__tests__/ProxiesView.ipv6.spec.ts

@@ -0,0 +1,51 @@
+import { describe, expect, it } from 'vitest'
+import { readFileSync } from 'node:fs'
+import { resolve } from 'node:path'
+
+// parseProxyUrl is not exported; assert on the source to lock in the
+// bracketed-IPv6 host alternative and exercise the regex directly.
+const source = readFileSync(
+  resolve(process.cwd(), 'src/views/admin/ProxiesView.vue'),
+  'utf8'
+)
+
+function extractRegex(): RegExp {
+  const match = source.match(/const regex =\s*\n?\s*(\/\^\(https\?[^;\n]+\/i)\n/)
+  expect(match, 'parseProxyUrl regex not found in ProxiesView.vue').toBeTruthy()
+  return new RegExp((match as RegExpMatchArray)[1].slice(1, -2), 'i')
+}
+
+describe('proxy batch URL parsing (IPv6 support)', () => {
+  it('keeps bracketed-IPv6 host alternative in the regex', () => {
+    expect(source).toContain('\\[[0-9a-f:.]+\\]')
+  })
+
+  const regex = extractRegex()
+
+  it.each([
+    ['socks5://[2001:db8::1]:1080', true],
+    ['socks5h://[2001:db8::1]:1080', true],
+    ['http://[::1]:8080', true],
+    ['socks5://user:pass@[2001:db8::1]:1080', true],
+    ['socks5://proxy.example.com:1080', true],
+    ['http://192.168.1.1:8080', true],
+    ['socks5://user:pass@proxy.example.com:1080', true],
+    // bare IPv6 without brackets is ambiguous with host:port — rejected
+    ['socks5://2001:db8::1:1080', false],
+    // unsupported schemes / malformed ports stay invalid
+    ['ftp://example.com:21', false],
+    ['socks5://example.com:port', false]
+  ])('%s => %s', (line, expected) => {
+    expect(regex.test(line)).toBe(expected)
+  })
+
+  it('extracts bare IPv6 host without brackets', () => {
+    const m = 'socks5://user:pass@[2001:db8::1]:1080'.match(regex)
+    expect(m).toBeTruthy()
+    const [, , username, password, rawHost, port] = m as RegExpMatchArray
+    expect(username).toBe('user')
+    expect(password).toBe('pass')
+    expect(rawHost.replace(/^\[|\]$/g, '')).toBe('2001:db8::1')
+    expect(port).toBe('1080')
+  })
+})