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>

Apis/page-fetcher-data/PageFetchDbContext.cs

@@ -0,0 +1,45 @@
+using Microsoft.EntityFrameworkCore;
+using PageFetcher.Data.Entities;
+
+namespace PageFetcher.Data;
+
+/// <summary>
+/// EF Core DbContext for the <c>pageFetcher</c> schema.
+/// Owns the <c>PageFetches</c> audit table.
+/// </summary>
+public sealed class PageFetchDbContext : DbContext
+{
+    public const string SchemaName = MigrationConstants.SchemaName;
+    public const string MigrationTableName = MigrationConstants.MigrationTableName;
+
+    public PageFetchDbContext(DbContextOptions<PageFetchDbContext> options) : base(options) { }
+
+    public DbSet<PageFetchEntity> PageFetches => Set<PageFetchEntity>();
+
+    protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
+    {
+        base.OnConfiguring(optionsBuilder);
+        optionsBuilder.UseSqlServer(x => x.MigrationsHistoryTable(MigrationTableName, SchemaName));
+    }
+
+    protected override void OnModelCreating(ModelBuilder modelBuilder)
+    {
+        modelBuilder.HasDefaultSchema(SchemaName);
+
+        modelBuilder.Entity<PageFetchEntity>(entity =>
+        {
+            entity.ToTable("PageFetches");
+            entity.HasKey(x => x.Id);
+            entity.Property(x => x.Id).HasMaxLength(64);
+            entity.Property(x => x.Url).HasMaxLength(2000).IsRequired();
+            entity.Property(x => x.CallerService).HasMaxLength(64).IsRequired();
+            entity.Property(x => x.Html).IsRequired();
+            entity.Property(x => x.Text).IsRequired();
+            entity.Property(x => x.ErrorMessage).HasMaxLength(2000);
+            entity.Property(x => x.CreatedAt).HasDefaultValueSql("SYSUTCDATETIME()");
+
+            entity.HasIndex(x => x.Url);
+            entity.HasIndex(x => x.CreatedAt);
+        });
+    }
+}