feat(web): add public master profiles

Add sanitized public GM profiles with publication controls, public /gm/{slug} pages, and links from public game surfaces.

Bump version -> 3.5.0

src/GmRelay.Bot/Migrations/V028__add_master_profiles.sql

@@ -0,0 +1,20 @@
+-- Public GM profiles for catalog and club trust pages.
+
+CREATE TABLE master_profiles (
+    id            UUID PRIMARY KEY DEFAULT gen_random_uuid(),
+    player_id     UUID NOT NULL UNIQUE REFERENCES players(id) ON DELETE CASCADE,
+    public_slug   VARCHAR(120),
+    is_public     BOOLEAN NOT NULL DEFAULT false,
+    display_name  VARCHAR(255) NOT NULL,
+    bio           TEXT,
+    created_at    TIMESTAMPTZ NOT NULL DEFAULT now(),
+    updated_at    TIMESTAMPTZ NOT NULL DEFAULT now()
+);
+
+CREATE UNIQUE INDEX ux_master_profiles_public_slug
+    ON master_profiles (lower(public_slug))
+    WHERE public_slug IS NOT NULL;
+
+CREATE INDEX ix_master_profiles_public
+    ON master_profiles (lower(public_slug))
+    WHERE is_public = true AND public_slug IS NOT NULL;