checkpoint: vault-load rewrite fix (c096705) + Amber verify as next step

CHECKPOINT-encryption.md

@@ -1,3 +1,59 @@
+# Checkpoint — Vault-load rewrite fix + Amber handshake lands (2026-09-11)
+
+## Where things are
+- Project: `/home/avi/Projects/Keynctr`
+- Branch: `master` @ **`c096705`** ("fix(vault): stop rewriting the vault on every
+  load; clippy cleanup"). Previous: `f917e5e` (Amber-compatible handshake).
+- Working tree: clean for tracked files (untracked leftovers unchanged — see older
+  "Still untracked" sections).
+- Verification: `cargo test` **200 passed / 0 failed**, `cargo clippy --all-targets`
+  0 warnings, `cargo fmt --check` clean, `cargo build --release` green.
+  (Frontend untouched this session; vite dev server still running on :5173.)
+
+## What was completed (this session)
+
+**Carried-forward open question — CLOSED, landed as `c096705`.**
+`migrate_vault_signer_modes` used to return `changed = true` unconditionally, so
+`App::load` re-encrypted and re-saved the vault on every single start. Now a change
+is reported only when `vault.version` actually moves: per-profile `signer_mode`
+normalisation was always a no-op (the serde default fills missing fields at parse
+time and the current version serialises it explicitly). The idempotency test was
+tightened to assert `changed == false` for a current-version vault. Also dropped a
+clone-on-Copy in `nip46_client.rs::get_public_key` (clippy warning from `f917e5e`).
+
+**`f917e5e` (committed earlier today, before this session):** Amber-compatible
+NIP-46 handshake — `bunker://` URIs accepted, URI authority key no longer treated
+as identity (Amber mints a per-connection comms key; real identity learned via
+`get_public_key` after the connect ack), 120 s human-approval window with the
+session held in Connecting (fail closed), absent `perms=` delegates enforcement to
+the signer, `send_rpc` honours its timeout. **On-device Amber round-trip has not
+been re-verified since this commit — that is the next task.**
+
+## Commits added (newest first)
+- `c096705` fix(vault): stop rewriting the vault on every load; clippy cleanup
+- `f917e5e` fix(signer): Amber-compatible handshake — bunker:// URIs, deferred
+  identity, ack wait (landed earlier today)
+
+## How to reproduce / exercise
+- Dev loop (from memory, unchanged): `npx vite --port 5173`, then
+  `NOSTR_GUI_DEV_URL=http://localhost:5173 KEYNCTR_ENABLE_GPU=1 npx electron .` in
+  `frontend/` (backend from `target/release/keynectr serve`). Rust edits need
+  rebuild + backend restart.
+- Exercise vault fix: start the app twice; the vault file's mtime should NOT change
+  on the second start when nothing was modified.
+
+## Deferred / next steps
+1. **Verify Amber end-to-end on device** (pair via Amber, sign a note, publish).
+2. Dead stub `src/signer/nip46_external.rs` (untracked, superseded by
+   `nip46_client.rs`) — delete or fold its docs; `deferred/SignerConnectionPanel.tsx.wip/`
+   stays deferred.
+3. `publish_profile_metadata` (kind 0) still signs locally — reroute through
+   `Signing` for external profiles.
+4. Step 4 (permissions UI), Step 5 (KDF upgrade), Step 6 (undo history),
+   Step 7 (rename/hygiene incl. `homepage` URL + 5 Prettier files) — unchanged.
+
+---
+
 # Checkpoint — External NIP-46 signing works end-to-end (2026-09-10)
 
 ## Where things are