feat: add page-fetcher-api — centralised Playwright page fetcher

Introduces page-fetcher-api, a new internal ASP.NET Core service that
centralises all web-page fetching through a single Playwright (headless
Chromium) browser instance. All fetches are persisted to the pageFetcher
SQL schema for auditing.

New projects:
- Apis/page-fetcher-api-models: FetchPageRequest, FetchPageResponse, IPageFetcherApiClient
- Apis/page-fetcher-data: PageFetchDbContext, PageFetchEntity, InitialSchema migration (schema: pageFetcher)
- Apis/page-fetcher-api: PlaywrightBrowserService (singleton), PageFetcherService, PageController

Changes to existing services:
- cv-matcher-api: JobTextExtractor now calls IPageFetcherApiClient instead of HttpClient
- cv-search-job: HtmlJobSearcher uses IPageFetcherApiClient (removes inline Playwright);
  CvSearchJobTask fetches individual job pages and applies keyword pre-filter before
  LLM call; passes pre-fetched JobDescription to cv-matcher-api to skip re-fetch
- common: add PageFetcherApiSettings
- docker-compose.yml, build.yml: add new service + env vars for callers

Closes #43

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Jobs/cv-search-job/Program.cs

@@ -14,6 +14,7 @@ using JobScheduler.Tasks;
 using Microsoft.EntityFrameworkCore;
 using Microsoft.Extensions.DependencyInjection;
 using Microsoft.Extensions.Hosting;
+using PageFetcher.Models;
 using Refit;
 using Serilog;
 using Common.Settings;
@@ -81,7 +82,19 @@ try
                 client.DefaultRequestHeaders.Add("X-Internal-Api-Key", key);
         });
 
-    builder.Services.AddHttpClient<HtmlJobSearcher>();
+    builder.Services.AddRefitClient<IPageFetcherApiClient>()
+        .ConfigureHttpClient((sp, client) =>
+        {
+            var config = sp.GetRequiredService<Microsoft.Extensions.Configuration.IConfiguration>();
+            var baseUrl = config["PageFetcherApi:BaseUrl"] ?? string.Empty;
+            if (!string.IsNullOrWhiteSpace(baseUrl))
+                client.BaseAddress = new Uri(baseUrl.TrimEnd('/') + "/");
+            var key = config["PageFetcherApi:InternalApiKey"];
+            if (!string.IsNullOrWhiteSpace(key))
+                client.DefaultRequestHeaders.Add("X-Internal-Api-Key", key);
+        });
+
+    builder.Services.AddSingleton<HtmlJobSearcher>();
     builder.Services.AddSingleton<CvSearchEmailSender>();
 
     builder.Services.AddSingleton<CvSearchJobTask>();