Add local login, agent extra log paths, IPv4/IPv6 metrics; remediate security audit findings

This is a large squashed commit covering two batches of prior uncommitted
work plus a full security-audit remediation pass, kept together because
go.mod/go.sum and several shared files (main.go, handler.go) were touched
by both and splitting risked non-building intermediate commits.

Features (built earlier, previously uncommitted):
- Local username/password login for single-tenant deployments with no
  SSO configured (api/localauth, alerting/internal/sessioncheck,
  sentryctl users, web/src/routes/login, metadata migrations 0040/0041).
- Remotely-editable additional log file paths for agents, on top of
  their existing primary source (api/agents, agent/sentry-agent
  extra-file-path diffing, web agent config UI).
- IPv4/IPv6 addresses reported alongside other host system metrics.

Security audit remediation (this pass, all live-verified in production):
- Critical: block ClickHouse SSRF table functions (url/remote/file/s3/...)
  in the raw-SQL query escape hatch.
- High: deny sensitive paths and require Admin to add agent
  extra_file_paths (Editor could previously point an agent at /etc/shadow
  or an SSH key); alerting webhook targets now validate against
  internal/metadata/loopback addresses, both at creation and send time;
  alerting's session middleware now enforces an Editor+ floor on
  mutating requests instead of "any authenticated session"; bumped
  goxmldsig to close a SAML signature-verification bypass (GO-2026-4753).
- Medium: per-IP login rate limiting; security response headers
  (HSTS/CSP/nosniff/X-Frame-Options/Referrer-Policy/Permissions-Policy)
  on web/nginx.conf; a DevCredentialWarnings check in every Go service's
  config loader, logging loudly at startup if a deployment is still on
  docker-compose.yml's literal dev-only credentials; dependency bumps
  (golang.org/x/text, grpc, x/net, quick-xml, h2) across every affected
  Go module and both Rust crates, including a previously-uncovered x/net
  vulnerability in deploy/operator; a new security-scan.yml CI workflow
  running cargo-deny/govulncheck/npm-audit, mirroring the existing
  license-compliance.yml matrix shape.
- Low: removed sentryctl's plaintext --password flag (shell
  history/`ps` exposure) in favor of stdin and a --password-stdin flag
  for reset-password's optional specific-password path; a dummy bcrypt
  comparison closes a login response-time username-enumeration
  side-channel.

web/src/lib/components/NavSidebar.svelte

@@ -1,6 +1,14 @@
 <script lang="ts">
 	import { page } from '$app/state';
-	import { getCurrentSession, enterpriseAuthBase, type CurrentSession } from '$lib/api';
+	import {
+		getCurrentSession,
+		enterpriseAuthBase,
+		localAuthEnabled,
+		getLocalSession,
+		logout,
+		type CurrentSession,
+		type LocalSession
+	} from '$lib/api';
 	import { getTheme, setTheme, type Theme } from '$lib/theme.svelte';
 	import { getDensity, toggleDensity } from '$lib/density.svelte';
 
@@ -16,6 +24,7 @@
 		{ href: '/alerts', label: 'Alerts', icon: '▲' },
 		{ href: '/data-sources', label: 'Data Sources', icon: '◈' },
 		{ href: '/agents', label: 'Agents', icon: '●' },
+		{ href: '/hosts', label: 'Hosts', icon: '▣' },
 		{ href: '/settings', label: 'Settings', icon: '⚙' }
 	];
 
@@ -29,6 +38,22 @@
 		getCurrentSession().then((s) => (session = s));
 	});
 
+	let localSession: LocalSession | null = $state(null);
+	$effect(() => {
+		if (!localAuthEnabled) return;
+		getLocalSession().then((s) => (localSession = s === 'disabled' ? null : s));
+	});
+
+	let loggingOut = $state(false);
+	async function handleLogout() {
+		loggingOut = true;
+		try {
+			await logout();
+		} finally {
+			window.location.href = '/login';
+		}
+	}
+
 	const themeOptions: { value: Theme; label: string }[] = [
 		{ value: 'dark', label: 'Dark' },
 		{ value: 'light', label: 'Light' },
@@ -60,6 +85,17 @@
 				<a class="switch signin" href="{enterpriseAuthBase}/auth/oidc/login">Sign in</a>
 			{/if}
 		</div>
+	{:else if localAuthEnabled && localSession}
+		<div class="tenant">
+			<div class="tenant-pill">
+				<span class="dot" aria-hidden="true"></span>
+				<span class="tenant-name">{localSession.username}</span>
+				<span class="role">{localSession.role}</span>
+			</div>
+			<button type="button" class="switch logout-btn" onclick={handleLogout} disabled={loggingOut}>
+				{loggingOut ? 'Signing out…' : 'Log out'}
+			</button>
+		</div>
 	{/if}
 
 	<nav aria-label="Main">
@@ -177,6 +213,18 @@
 	.switch:hover {
 		color: var(--color-accent);
 	}
+	.logout-btn {
+		background: none;
+		border: none;
+		font-family: var(--font-ui);
+		width: 100%;
+		text-align: left;
+		cursor: pointer;
+	}
+	.logout-btn:disabled {
+		cursor: default;
+		opacity: 0.6;
+	}
 	.switch.signin {
 		display: block;
 		padding: var(--space-2) var(--space-3);