docs: concept annexation, provider/reference docs, ACT-1 groundwork

Mosaic concepts pages now own the adapted content; source/license
metadata under docs/reference/concepts. Adds ACT-1 agent-context
planning capture, pinned concept test package + preparation utility,
foundation observation notes (durability, evidence, federation,
onboarding, workflow), and the #1495 consolidation assessment.
TOOLS.md updated for the host-dev launcher.

docs/plans/act-1-tests/fixtures/context-inventory.json

@@ -0,0 +1,37 @@
+{
+  "synthetic": true,
+  "agent": "darkwing-test",
+  "inputs": [
+    {
+      "path": "agents/darkwing-test/SOUL.md",
+      "kind": "SOUL",
+      "included": true,
+      "truncated": false
+    },
+    {
+      "path": "contracts/CONSTITUTION.md",
+      "kind": "CONSTITUTION",
+      "required": true,
+      "included": true,
+      "truncated": true
+    },
+    {
+      "path": "SOUL.md",
+      "kind": "SOUL",
+      "included": false,
+      "reason": "not agent-owned"
+    },
+    {
+      "path": "contracts/SOUL.md",
+      "kind": "SOUL",
+      "included": false,
+      "reason": "no fallback"
+    },
+    {
+      "path": "USER.md",
+      "kind": "USER",
+      "included": true,
+      "truncated": false
+    }
+  ]
+}