feat: add multi-option reschedule voting

src/GmRelay.Bot/Migrations/V009__add_multi_option_reschedule_votes.sql

@@ -0,0 +1,35 @@
+-- Multi-option reschedule voting with a deadline.
+
+ALTER TABLE reschedule_proposals
+    ADD COLUMN voting_deadline_at TIMESTAMPTZ,
+    ADD COLUMN selected_option_id UUID;
+
+CREATE TABLE reschedule_options (
+    id              UUID PRIMARY KEY DEFAULT gen_random_uuid(),
+    proposal_id     UUID NOT NULL REFERENCES reschedule_proposals(id) ON DELETE CASCADE,
+    proposed_at     TIMESTAMPTZ NOT NULL,
+    display_order   INTEGER NOT NULL CHECK (display_order BETWEEN 1 AND 3),
+    created_at      TIMESTAMPTZ NOT NULL DEFAULT now(),
+    UNIQUE (proposal_id, id),
+    UNIQUE (proposal_id, display_order),
+    UNIQUE (proposal_id, proposed_at)
+);
+
+CREATE TABLE reschedule_option_votes (
+    id              UUID PRIMARY KEY DEFAULT gen_random_uuid(),
+    proposal_id     UUID NOT NULL REFERENCES reschedule_proposals(id) ON DELETE CASCADE,
+    player_id       UUID NOT NULL REFERENCES players(id) ON DELETE CASCADE,
+    option_id       UUID NOT NULL,
+    voted_at        TIMESTAMPTZ NOT NULL DEFAULT now(),
+    UNIQUE (proposal_id, player_id),
+    FOREIGN KEY (proposal_id, option_id)
+        REFERENCES reschedule_options(proposal_id, id)
+        ON DELETE CASCADE
+);
+
+CREATE INDEX ix_reschedule_voting_deadline
+    ON reschedule_proposals (voting_deadline_at)
+    WHERE status = 'Voting';
+
+CREATE INDEX ix_reschedule_option_votes_option
+    ON reschedule_option_votes (option_id);