feat(matching): move BotRoster from hardcoded fixture to DB-backed seed

Phase 3 shipped the AI rank battle bot pool as a hardcoded 8-entry list
inlined in SVSim.EmulatedEntrypoint/Matching/BotRoster.cs — editing meant
recompiling. Per PLAN.md 2026-06-02 item (d), move it to a Bootstrap
importer so the roster lives in seeds/bot-roster.json and the DB.

Shape mirrors PracticeOpponent end-to-end:
- BotRosterEntry (SVSim.Database/Models) — PK = AiId via the Id passthrough
  pattern. DbSet<BotRosterEntry> BotRoster on SVSimDbContext.
- AddBotRoster migration (DDL only, per migrations-are-DDL-only rule).
- seeds/bot-roster.json — 8 rows preserving the current prod-verified
  cosmetic ids (sleeve 704141010 / emblem 400001100 / degree 120027 /
  field 5) and series-1 ai_ids from rm_ai_setting.csv (1111..1181).
- BotRosterSeed POCO + BotRosterImporter (idempotent upsert keyed by AiId,
  leaves seed-missing rows intact). Wired into SVSim.Bootstrap/Program.cs
  next to PracticeOpponentImporter.
- IGlobalsRepository.GetBotRoster() + impl.

IBotRoster.Pick → PickAsync because BotRoster now depends on the transient
IGlobalsRepository. RankBattleController awaits the new signature. The
deterministic hash-on-ctx invariant (same ctx → same bot, so /ai_<fmt>/start
retries pick the same opponent) is preserved.

DI: AddSingleton<IBotRoster> → AddTransient (matches IGlobalsRepository's
lifetime). Test fixture's SeedGlobalsAsync also runs the importer so
RankBattleControllerTests + the rewritten BotRosterTests both see seeded
rows.

Tests: 931 → 936 passing. Existing 3 BotRosterTests reshaped for the DB
backing + 1 new "throws on empty roster" guard; 4 new
BotRosterImporterTests mirror PracticeOpponentImporterTests
(round-trip / idempotent / seed-missing-row-intact / ai_id=0 skip).

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

SVSim.Database/Migrations/SVSimDbContextModelSnapshot.cs

@@ -756,6 +756,66 @@ namespace SVSim.Database.Migrations
                     b.ToTable("Battlefields");
                 });
 
+            modelBuilder.Entity("SVSim.Database.Models.BotRosterEntry", b =>
+                {
+                    b.Property<int>("Id")
+                        .HasColumnType("integer");
+
+                    b.Property<int>("AiId")
+                        .HasColumnType("integer");
+
+                    b.Property<int>("BattlePoint")
+                        .HasColumnType("integer");
+
+                    b.Property<int>("CharaId")
+                        .HasColumnType("integer");
+
+                    b.Property<int>("ClassId")
+                        .HasColumnType("integer");
+
+                    b.Property<string>("CountryCode")
+                        .IsRequired()
+                        .HasColumnType("text");
+
+                    b.Property<DateTime>("DateCreated")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.Property<DateTime?>("DateUpdated")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.Property<int>("DegreeId")
+                        .HasColumnType("integer");
+
+                    b.Property<int>("EmblemId")
+                        .HasColumnType("integer");
+
+                    b.Property<int>("FieldId")
+                        .HasColumnType("integer");
+
+                    b.Property<int>("IsMasterRank")
+                        .HasColumnType("integer");
+
+                    b.Property<int>("IsOfficial")
+                        .HasColumnType("integer");
+
+                    b.Property<int>("MasterPoint")
+                        .HasColumnType("integer");
+
+                    b.Property<int>("Rank")
+                        .HasColumnType("integer");
+
+                    b.Property<int>("SleeveId")
+                        .HasColumnType("integer");
+
+                    b.Property<string>("UserName")
+                        .IsRequired()
+                        .HasColumnType("text");
+
+                    b.HasKey("Id");
+
+                    b.ToTable("BotRoster");
+                });
+
             modelBuilder.Entity("SVSim.Database.Models.BuildDeckProductEntry", b =>
                 {
                     b.Property<int>("Id")