feat(communication): federate tenant collaboration with signed delivery

backend/db/migrations/0076_collaboration_federation.sql

@@ -0,0 +1,67 @@
+CREATE TABLE collaboration_federation_identity (
+    singleton boolean PRIMARY KEY DEFAULT true CHECK(singleton),
+    instance_id uuid NOT NULL UNIQUE,
+    key_id uuid NOT NULL,
+    public_key text NOT NULL,
+    private_key_cipher jsonb NOT NULL,
+    created_at timestamptz NOT NULL DEFAULT now()
+);
+CREATE TABLE collaboration_partners (
+    tenant_id bigint NOT NULL REFERENCES tenants(id) ON DELETE CASCADE,
+    origin text NOT NULL,
+    instance_id uuid NOT NULL,
+    key_id uuid NOT NULL,
+    public_key text NOT NULL,
+    active boolean NOT NULL DEFAULT true,
+    updated_at timestamptz NOT NULL DEFAULT now(),
+    PRIMARY KEY(tenant_id,origin)
+);
+CREATE TABLE collaboration_federation_nonces (
+    origin text NOT NULL,
+    nonce uuid NOT NULL,
+    expires_at timestamptz NOT NULL,
+    PRIMARY KEY(origin,nonce)
+);
+CREATE TABLE collaboration_remote_bindings (
+    id uuid PRIMARY KEY DEFAULT gen_random_uuid(),
+    tenant_id bigint NOT NULL REFERENCES tenants(id) ON DELETE CASCADE,
+    principal_id uuid NOT NULL REFERENCES collaboration_principals(id) ON DELETE CASCADE,
+    origin text NOT NULL,
+    room_id uuid NOT NULL,
+    invitation_id uuid NOT NULL,
+    status text NOT NULL DEFAULT 'pending' CHECK(status IN ('pending','active','revoked','declined')),
+    invitation jsonb NOT NULL,
+    snapshot jsonb,
+    revision bigint NOT NULL DEFAULT 0,
+    last_read_seq bigint NOT NULL DEFAULT 0,
+    sync_seq bigint NOT NULL DEFAULT 0,
+    sync_at timestamptz,
+    last_error text,
+    UNIQUE(principal_id,origin,room_id)
+);
+CREATE TABLE collaboration_remote_messages (
+    binding_id uuid NOT NULL REFERENCES collaboration_remote_bindings(id) ON DELETE CASCADE,
+    id uuid NOT NULL,
+    seq bigint NOT NULL,
+    payload jsonb NOT NULL,
+    PRIMARY KEY(binding_id,id),
+    UNIQUE(binding_id,seq)
+);
+CREATE TABLE collaboration_outbox (
+    id uuid PRIMARY KEY DEFAULT gen_random_uuid(),
+    dedup_key text NOT NULL UNIQUE,
+    tenant_id bigint NOT NULL REFERENCES tenants(id) ON DELETE CASCADE,
+    principal_id uuid NOT NULL REFERENCES collaboration_principals(id),
+    origin text NOT NULL,
+    binding_id uuid REFERENCES collaboration_remote_bindings(id) ON DELETE CASCADE,
+    room_id uuid REFERENCES collaboration_rooms(id) ON DELETE CASCADE,
+    action text NOT NULL,
+    payload jsonb NOT NULL,
+    status text NOT NULL DEFAULT 'pending' CHECK(status IN ('pending','sent','failed')),
+    attempts integer NOT NULL DEFAULT 0,
+    next_attempt_at timestamptz NOT NULL DEFAULT now(),
+    lease_until timestamptz,
+    last_error text,
+    created_at timestamptz NOT NULL DEFAULT now()
+);
+CREATE INDEX collaboration_outbox_pending ON collaboration_outbox(next_attempt_at) WHERE status='pending';