Initial commit: Theriapolis baseline at port/godot branch point

Captures the pre-Godot-port state of the codebase. This is the rollback
anchor for the Godot port (M0 of theriapolis-rpg-implementation-plan-godot-port.md).
All Phase 0 through Phase 6.5 work is included; Phase 7 is in flight.

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

Theriapolis.Core/Persistence/SaveMigrations/V5ToV6Migration.cs

@@ -0,0 +1,27 @@
+namespace Theriapolis.Core.Persistence.SaveMigrations;
+
+/// <summary>
+/// Phase 6 M2 — additive migration from save schema v5 (Phase 5 ship) to
+/// v6 (Phase 6 reputation core). Non-destructive: every v5 field carries
+/// over unchanged. The new <see cref="SaveBody.ReputationState"/> is
+/// already initialised to a fresh empty <see cref="ReputationSnapshot"/>
+/// by the SaveBody constructor, so this migration just bumps the header
+/// version.
+///
+/// Phase 5's placeholder <see cref="SaveBody.Factions"/> and
+/// <see cref="SaveBody.Reputation"/> dictionaries were never populated
+/// (Phase 5 didn't ship the reputation system), so we don't need to
+/// translate any data — they stay empty and ignored.
+/// </summary>
+public sealed class V5ToV6Migration : ISaveMigration
+{
+    public int FromVersion => 5;
+    public int ToVersion   => 6;
+
+    public void Apply(SaveHeader header, SaveBody body)
+    {
+        // Body fields all default-initialise to empty in SaveBody — the
+        // ReputationState is already a fresh ReputationSnapshot. Phase-5
+        // saves had nothing to translate, so this is a pure version bump.
+    }
+}