Document the 1.4.0 release candidate

docs/MIGRATING_FROM_V1.md

@@ -19,6 +19,36 @@ Read [compatibility](COMPATIBILITY.md), [legacy and no-AST operation](LEGACY_AND
 
 Disposable index and cache schemas may change. Rebuild them rather than copying them as authority.
 
+## Maintained v1.0.0 migration evidence
+
+`make migration-m5` archives and executes the actual annotated `v1.0.0` release, then opens its
+fixture, index, and active proposal through DocForge 1.4.0. The frozen tag object is
+`2d7d306a37da89f1c860c7f0be161c45386acf61`; it identifies commit
+`593c173b453236a6872d0a4e88e7a51a67a21cde`.
+
+The tagged release contains an inherited identity mismatch that the migration proof records
+rather than hiding: distribution metadata says `1.0.0`, while `docforge.__version__` and the MCP
+server report `0.15.0`. DocForge 1.4.0 replaces that duplicated state with one authoritative
+version and requires its package and server values to agree.
+
+The maintained fixture evidence is exact:
+
+- Canonical collection hash:
+  `9fde91b6b08669177d690cdf9f91b162120baee1f7e24b05fec67f56617f286a`.
+- Graph snapshot hash:
+  `45bef8b0e1a4dac976e096dcf8f9048e1268211cd7f7638cdf99951428ec0500`.
+- Source hash: `0aa6ad13a95355102300a69b2f9d06883c301d63e2624b083e45f15102dab504`.
+- Active proposal hash:
+  `2c055dfae45443b4a4d9d4087ef70959e7293beae8d27acb14ffffe52eca7111`.
+- Proposal-file hash:
+  `4658d494b43bd7c6cc3e3f5933a2c878c817b52bc4566e9e8429e7b8e43ca007`.
+
+Current loading preserves all five identities and every canonical byte. It rebuilds the disposable
+index from schema 1 to schema 3 without changing the graph or active proposal. All 20 tagged CLI
+commands remain in the current 28-command surface, and all 25 tagged MCP tools remain in the
+current 36-tool application-enabled surface. These counts describe the maintained rehearsal, not
+a promise that every additive current command belongs in a legacy binding.
+
 ## Recommended migration
 
 1. Record the v1 package version, adapter identity, project descriptor, canonical source hash,