wallet: derive the key pool from a seed, so a phrase could bring it back (#93)

Adds BIP32 derivation behind the wallet key pool, with no user-facing way to create a seed yet. wallet.dat gains hdmaster/hdchaincode/hdnext; the mnemonic is never stored. TopUpKeyPool derives m/n' when a seed exists and falls back to a random key, with a log line, if derivation fails. New -selftest=wallet-hd, wired into make tests on both platforms.

1 files changed, 2 insertions, 1 deletions

diff --git a/src/Makefile b/src/Makefile
index d4b1837..bbdc9e2 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -50,7 +50,7 @@ IMGUI_OBJS = obj/imgui.o obj/imgui_draw.o obj/imgui_tables.o \
 NODE_OBJS = obj/util.o obj/script.o obj/db.o obj/net.o obj/main.o \
             obj/market.o obj/sha.o obj/nostr.o obj/randomx_pow.o \
             obj/btfaddr.o obj/btfchan.o obj/btfrv.o obj/btftunnel.o obj/rpc.o \
-            obj/selftest.o
+            obj/selftest.o obj/bip32.o
 
 GUI_OBJS = obj/gui.o obj/main_gui.o
 
@@ -131,3 +131,4 @@ test_bip32: test_bip32.cpp bip32.cpp bip32.h bip39_english.h
 tests: test_bip32 bitflash-node
         ./test_bip32
         ./bitflash-node -selftest=wallet-keypool
+        ./bitflash-node -selftest=wallet-hd