fix(security): gate AI tools by user ability and block admin-URL SSRF

The AI chat assistant scoped tool queries by company but ignored the
per-user Bouncer abilities the rest of the app enforces, so any `use ai`
holder could read customers, invoices, payments, and company financials
their role couldn't otherwise see. Each AiTool now declares a required
ability (entity-aligned); the registry hides unauthorized tools from the
model and refuses to execute them as a backstop.

Separately, admin/owner-supplied URLs were fetched server-side with no
guard against private/reserved targets (SSRF): the AI base URL, the
CurrencyConverter "DEDICATED" exchange-rate URL, and S3/Spaces file-disk
endpoints. A shared PrivateNetworkGuard now backs a PublicHttpUrl
validation rule (save-time) and runtime guards in each driver.

- AiTool::requiredAbility() + mapping across all 12 tools
- AiToolRegistry filters schemas() by ability and re-checks in execute()
- PrivateNetworkGuard / BlockedUrlException / PublicHttpUrl rule (new)
- Rule wired into AI config (service + 3 controllers), exchange-rate,
  and file-disk endpoints; runtime guards in OpenRouterDriver,
  CurrencyConverterDriver, and FileDiskService
- Tests for ability filtering, the guard, the rule, and 422 rejections

tests/Unit/OpenRouterDriverTest.php

@@ -0,0 +1,26 @@
+<?php
+
+use App\Support\Ai\AiException;
+use App\Support\Ai\OpenRouterDriver;
+
+/**
+ * Runtime SSRF backstop: even if a private base URL slips past validation (e.g.
+ * config saved before the rule existed, or DNS rebinding), the driver must refuse
+ * to make the request.
+ */
+test('rejects a private base URL before making any request', function () {
+    $driver = new OpenRouterDriver('test-key', ['base_url' => 'http://169.254.169.254']);
+
+    expect(fn () => $driver->validateConnection())->toThrow(AiException::class);
+});
+
+test('the thrown AI exception carries the invalid_base_url error key', function () {
+    $driver = new OpenRouterDriver('test-key', ['base_url' => 'http://127.0.0.1:11434']);
+
+    try {
+        $driver->validateConnection();
+        test()->fail('Expected AiException was not thrown');
+    } catch (AiException $e) {
+        expect($e->errorKey)->toBe('invalid_base_url');
+    }
+});