Merge remote-tracking branch 'origin/staging' into feat/workspace-metadata-versioning-patch

# Conflicts:
#	src/agent/heartbeat.rs
#	src/db/libsql_migrations.rs

migrations/V15__document_versions.sql

@@ -0,0 +1,23 @@
+-- Document version history for workspace files.
+-- Every content update saves the previous content as a version,
+-- enabling rollback and audit trails.
+
+CREATE TABLE memory_document_versions (
+    id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
+    document_id UUID NOT NULL REFERENCES memory_documents(id) ON DELETE CASCADE,
+    version INTEGER NOT NULL,
+    content TEXT NOT NULL,
+    content_hash TEXT NOT NULL,
+    created_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),
+    changed_by TEXT,
+    UNIQUE(document_id, version)
+);
+
+CREATE INDEX idx_doc_versions_lookup
+    ON memory_document_versions(document_id, version DESC);
+
+-- GIN index on metadata for JSON path queries (used by hygiene to find
+-- .config documents with hygiene.enabled). The metadata column already
+-- exists (V1) but was never indexed.
+CREATE INDEX idx_memory_documents_metadata
+    ON memory_documents USING GIN (metadata jsonb_path_ops);