docs: record what the multiple-profiles plan built, and the places it chose differently

Phases 1–8 are implemented, in order, one commit each; Phase 9 is the
rollout and stays as written. The plan's phases are kept as the reasoning,
and the table at the top says where the build chose differently: the
repair reads before it writes and hands the listing its result; one
WalletAttached outcome with two ways in; the node stop and the relay scope
injected for their tests; the default save that cannot crash; a
ProfilesViewModel over flows; a NewProfileWriter and a route flag where the
plan expected the create screen's existing writer to serve; the colliding
id on the outcome rather than on the enum; the DAO's own requests left
unowned because they fetch public kinds; the inbox reopened by re-indexing
each wrap in its own transaction rather than by lifting the unseal branch
out; and the round trip's A made through the create view model with a
never-started PhoenixBusiness for the switch to stop.

Three things found on the way and in no phase are recorded beside the
table: the library's unsynchronised global-preferences cache, reached by
two threads at once for the first time, now behind JvmGlobalPrefs on the
jvm target; the same cache's consequence for tests that construct the
sovereign view model; and the gift wrap seal's link to its wrap, a foreign
key that existed and was never written until the inbox sweep asked the
question it answers.

The README's row and reading order say the note is built, and name
switchToIdentity where they named switchToWallet.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Pulled-From: curated/curated@29027f2b92

docs/README.md

@@ -58,8 +58,9 @@ The npub sign-in note is a phased plan that has been built, and reads as that
 plan's out-of-scope note answered: it takes the `Identity` type and the sign-in
 machine as given and asks what an identity with no secret is for, before it asks
 how to build one; read its table of where the build chose differently first.
-The multiple-profiles note is a phased plan that has not been built, and reads as
-the third of the sign-in notes: it asks what happens when the device holds two
+The multiple-profiles note is a phased plan that has been built, and reads as the
+third of the sign-in notes: it asks what happens when the device holds two
 identities, and its first phase changes one rule the other two share — a seed's
 key becomes a credential like any other — so read it with `StoredIdentity.merge`,
-`SovereignWalletViewModel.switchToWallet` and the startup screen open.
+`SovereignWalletViewModel.switchToIdentity` and the startup screen open, and read
+its table of where the build chose differently first.