feat(P6/T01): Phase 6 schema — WidgetAdapterSpec, contracts, widgets.adapter_spec_id

Adds Phase 6 tables: envelope_emission_contracts, interaction_reporting_contracts,
widget_adapter_specs. Adds adapter_spec_id FK to widgets and api_key to hubs.
Seeds v1.0 contracts in migration. Registers Phase 6 controller types and routes.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Application/Schema.sql

@@ -312,3 +312,70 @@ CREATE TABLE confidence_annotations (
 );
 
 CREATE INDEX confidence_annotations_proposal_id_idx ON confidence_annotations (proposal_id);
+
+-- ============================================================
+-- Phase 6 — Cross-Framework UI Adaptation Layer
+-- ============================================================
+
+-- Formalises the rules for widget envelope emission: which data-* attributes
+-- are required, their format, and the contract version.
+CREATE TABLE envelope_emission_contracts (
+    id UUID DEFAULT uuid_generate_v4() PRIMARY KEY NOT NULL,
+    contract_version TEXT NOT NULL UNIQUE,   -- e.g. "1.0", "1.1"
+    required_attributes JSONB NOT NULL,
+    -- e.g. ["data-widget-id", "data-view-context", "data-hub-id"]
+    optional_attributes JSONB NOT NULL DEFAULT '[]',
+    validation_rules JSONB NOT NULL DEFAULT '{}',
+    -- machine-readable rules: format checks, presence guards
+    description TEXT,
+    status TEXT NOT NULL DEFAULT 'active',
+    -- status values: draft | active | superseded
+    created_at TIMESTAMP WITH TIME ZONE DEFAULT now() NOT NULL
+);
+
+CREATE INDEX envelope_emission_contracts_status_idx ON envelope_emission_contracts (status);
+
+-- Standardised REST interface contract for external event and annotation
+-- submission — used by non-IHP adapters.
+CREATE TABLE interaction_reporting_contracts (
+    id UUID DEFAULT uuid_generate_v4() PRIMARY KEY NOT NULL,
+    contract_version TEXT NOT NULL UNIQUE,   -- e.g. "1.0"
+    endpoint_path TEXT NOT NULL,             -- e.g. "/api/v1/interaction-events"
+    accepted_event_types JSONB NOT NULL,     -- e.g. ["clicked","viewed","submitted"]
+    required_fields JSONB NOT NULL,
+    -- minimum payload: widget_id, hub_id, event_type, occurred_at
+    auth_scheme TEXT NOT NULL DEFAULT 'bearer',
+    description TEXT,
+    status TEXT NOT NULL DEFAULT 'active',
+    created_at TIMESTAMP WITH TIME ZONE DEFAULT now() NOT NULL
+);
+
+CREATE INDEX interaction_reporting_contracts_status_idx ON interaction_reporting_contracts (status);
+
+-- Describes how a specific UI technology maps to IHF widget protocol obligations.
+CREATE TABLE widget_adapter_specs (
+    id UUID DEFAULT uuid_generate_v4() PRIMARY KEY NOT NULL,
+    name TEXT NOT NULL UNIQUE,         -- e.g. "react-18", "vue-3", "web-component"
+    framework TEXT NOT NULL,           -- e.g. "react", "vue", "vanilla"
+    version TEXT NOT NULL,             -- adapter spec version, e.g. "1.0"
+    envelope_contract_id UUID REFERENCES envelope_emission_contracts(id),
+    reporting_contract_id UUID REFERENCES interaction_reporting_contracts(id),
+    status TEXT NOT NULL DEFAULT 'draft',
+    -- status values: draft | active | deprecated
+    notes TEXT,
+    created_at TIMESTAMP WITH TIME ZONE DEFAULT now() NOT NULL,
+    updated_at TIMESTAMP WITH TIME ZONE DEFAULT now() NOT NULL
+);
+
+CREATE INDEX widget_adapter_specs_framework_idx ON widget_adapter_specs (framework);
+CREATE INDEX widget_adapter_specs_status_idx ON widget_adapter_specs (status);
+
+-- Link widgets to their adapter spec (null = native IHP widget).
+ALTER TABLE widgets
+    ADD COLUMN adapter_spec_id UUID REFERENCES widget_adapter_specs(id);
+
+CREATE INDEX widgets_adapter_spec_id_idx ON widgets (adapter_spec_id);
+
+-- Per-hub API key for bearer-token auth on the interaction reporting endpoint.
+ALTER TABLE hubs
+    ADD COLUMN api_key TEXT;