feat(rank): RankProgressService — pure +100/-50 tier-floored math

Reads RankInfoEntry.LowerLimitPoint from ranks.csv (via IGlobalsRepository)
for main-tier floors — no hardcoded thresholds. Master (Point=50000) and
Grand Master (MP-based, floor 5000) branch handles the post-Master path.
GetAsync is a read-only snapshot used later by AI-start's SelfInfo.

13 unit tests cover first-win, loss floors (0, Beginner→D, D→D0), win
crossing 50000, MP awards at Master, GM promotion at MP≥5000, GM floor
protecting against Master demotion, format separation, Crossover throw.

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

SVSim.Database/Services/RankProgress/IRankProgressService.cs

@@ -0,0 +1,46 @@
+using SVSim.Database.Enums;
+using SVSim.Database.Models;
+
+namespace SVSim.Database.Services.RankProgress;
+
+/// <summary>
+/// Wire-shape result of a single rank-battle finish grant. All fields map 1:1 to
+/// <c>RankBattleFinishResponseDto</c> keys the client reads via GetValueOrDefault
+/// in Wizard/RankBattleFinishTask.cs:57-63.
+/// </summary>
+/// <param name="Rank">rank_id post-grant (1..29).</param>
+/// <param name="AfterBattlePoint">Point post-grant (accumulated).</param>
+/// <param name="AfterMasterPoint">MasterPoint post-grant (accumulated).</param>
+/// <param name="BattlePoint">Signed Point delta (+100/-50/0).</param>
+/// <param name="MasterPoint">Signed MasterPoint delta.</param>
+/// <param name="IsMasterRank">True iff Rank == 25.</param>
+/// <param name="IsGrandMasterRank">True iff Rank &gt;= 26.</param>
+public sealed record RankProgressResult(
+    int Rank,
+    int AfterBattlePoint,
+    int AfterMasterPoint,
+    int BattlePoint,
+    int MasterPoint,
+    bool IsMasterRank,
+    bool IsGrandMasterRank);
+
+public interface IRankProgressService
+{
+    /// <summary>
+    /// Applies a +100 (win) or -50 (loss) delta to the viewer's rank progression in the
+    /// given format, respecting tier floors from <c>ranks.csv</c>'s LowerLimitPoint column.
+    /// Creates a ViewerRankProgress row for (viewer, format) if none exists. Caller must
+    /// have loaded the viewer with <c>.Include(v =&gt; v.RankProgress)</c> and must call
+    /// <c>SaveChangesAsync</c> after this returns.
+    /// </summary>
+    /// <param name="format">Must be Format.Rotation or Format.Unlimited.</param>
+    Task<RankProgressResult> GrantAsync(
+        Viewer viewer, Format format, bool isWin, CancellationToken ct = default);
+
+    /// <summary>
+    /// Read-only current progression snapshot for (viewer, format). Returns a zero-value
+    /// result if no row exists. Does not mutate the viewer or hit the DB.
+    /// </summary>
+    Task<RankProgressResult> GetAsync(
+        Viewer viewer, Format format, CancellationToken ct = default);
+}