sciagent code + Gitea Actions CI/CD

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

be0/migrations/014_registration_otp.sql

@@ -0,0 +1,20 @@
+-- Registration email verification via 6-digit OTP (replaces magic-link issuance on register).
+-- Apply after 013_email_verification.sql:
+--   docker exec -i initiative-postgres psql -U initiative -d initiatives < be0/migrations/014_registration_otp.sql
+
+CREATE TABLE IF NOT EXISTS registration_otp_codes (
+  id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
+  user_id UUID NOT NULL REFERENCES users(id) ON DELETE CASCADE,
+  otp_hash TEXT NOT NULL,
+  expires_at TIMESTAMPTZ NOT NULL,
+  failed_attempts INT NOT NULL DEFAULT 0,
+  used_at TIMESTAMPTZ,
+  created_at TIMESTAMPTZ NOT NULL DEFAULT now()
+);
+
+CREATE INDEX IF NOT EXISTS idx_registration_otp_codes_user_pending
+  ON registration_otp_codes (user_id)
+  WHERE used_at IS NULL;
+
+COMMENT ON TABLE registration_otp_codes IS
+  'Hashed 6-digit OTP for register verification; pending rows deleted when superseded by resend.';