Add measure-document linking

Introduce the ability to link measures to documents, following the
existing pattern used by controls and risks. This includes:

- Database migration for measures_documents join table
- Coredata MeasureDocument struct with insert/delete operations
- Document service methods for listing/counting by measure ID
- Measure service CreateDocumentMapping/DeleteDocumentMapping methods
- Cleanup of measure-document mappings on document archive
- GraphQL mutations, inputs, payloads, and Measure.documents field
- DocumentConnection.TotalCount support for measure resolver
- MCP linkMeasure/unlinkMeasure updated to support documents
- MCP listMeasureDocuments tool
- Frontend MeasureDocumentsTab with LinkedDocumentsCard integration
- Authorization actions for measure document mapping
- E2e tests for measure document mapping

Signed-off-by: Sacha Al Himdani <sacha@getprobo.com>

pkg/coredata/migrations/20260403T120000Z.sql

@@ -0,0 +1,22 @@
+-- Copyright (c) 2025-2026 Probo Inc <hello@getprobo.com>.
+--
+-- Permission to use, copy, modify, and/or distribute this software for any
+-- purpose with or without fee is hereby granted, provided that the above
+-- copyright notice and this permission notice appear in all copies.
+--
+-- THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
+-- REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
+-- AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
+-- INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
+-- LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
+-- OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
+-- PERFORMANCE OF THIS SOFTWARE.
+
+CREATE TABLE measures_documents (
+    measure_id TEXT NOT NULL REFERENCES measures(id) ON DELETE CASCADE,
+    document_id TEXT NOT NULL REFERENCES documents(id),
+    organization_id TEXT NOT NULL,
+    tenant_id TEXT NOT NULL,
+    created_at TIMESTAMP WITH TIME ZONE NOT NULL,
+    PRIMARY KEY (measure_id, document_id)
+);