build the secret store: one key per purpose, none in .env

.env now holds PORT and POSTGRES_URL. Every encryption and signing key lives in
$OFFICER_ROOT/secrets/officer-keys.db — 0600, 0700 directory, owned by the
service user, created on first use.

The design doc planned to move ONE at-rest key into the store. What shipped
splits it: headscale, wallet, photos, jellyfin, invoiceshelf, vault and
service-connections each get their own, plus jwt. VAULT_STORE_KEY encrypted all
seven, so one leak opened all of them — and it was named after whichever plugin
needed it first, which is why it read as safe to change if you did not run a
vault. A core install bootstraps two, jwt and headscale; the rest appear when
their plugin first asks.

The file IS the secret. No second key unlocks it, because a key beside the store
it opens buys nothing. The gain was never secrecy, it is blast radius: bun
auto-loads .env into all twenty pm2 processes, so a key there is readable from
/proc/<pid>/environ of twenty processes — officer-music held the key that
decrypts wallet seed envelopes.

Two defects found by testing the store rather than reading it, both of which
would have shipped:

  The WAL was 0644. Enabling WAL creates -wal and -shm at 0644 rather than
  inheriting the database's mode, and a freshly written key lives in the WAL
  before checkpoint — so the 0600 on the database was decorative. The 0700
  directory covered it, but only until someone loosened the directory.

  PRAGMA journal_mode = WAL takes an exclusive lock, and busy_timeout was set
  AFTER it. With twelve concurrent openers, six died on that line with
  SQLITE_BUSY. Every sidecar opens this store at boot, so they open it
  simultaneously by definition: most of them would have failed to start on a cold
  boot and none on a warm one. Fixed by ordering the pragmas; re-tested with
  twelve racing processes, one key, one row.

crypto.ts takes a purpose as its first argument now, which the design doc had
explicitly promised would not happen — 32 call sites across seven query modules.
That promise is corrected in the doc rather than quietly dropped.

Also live, not just comments: wallet/upstream.ts gated wallet storage on
process.env.VAULT_STORE_KEY and would have reported "unconfigured" forever. It
asks the store now, and the question it answers changed — not "did somebody set a
variable" but "can this process open the store", since the key is created on
demand.

assertSecretsClosed covers the store, its directory and its WAL. The jwt key
mints owner tokens, so a member's shell reading it is strictly worse than the
.env leak that check was written for.

Not typechecked: node_modules is empty and installs are frozen, so the
officerdb/secret-store subpath could not be resolved at runtime here — verified
that officerdb/types fails identically, so it is the empty tree and not the new
export. The store module itself was tested directly: creation, idempotence across
processes, hasKey not creating, permissions, and the twelve-way race. Every
changed file parses; the setup section runs and degrades correctly when the
import is unavailable.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

src/workspaces/officerdev/src/apps/Wallet/dialogs/CreateWalletDialog.tsx

@@ -37,7 +37,7 @@ import {
 //              close until the owner confirms they wrote it down.
 //   everything else — a connection to somebody's node or account, so it is a config blob, no seed at all.
 //
-// Wallet creation is refused outright when VAULT_STORE_KEY is unconfigured. The form says so up front
+// Wallet creation is refused outright when the wallet's at-rest key is unreachable. The form says so up front
 // rather than letting the submit fail with a crypto error.
 
 type CreateWalletDialogProps = {
@@ -253,7 +253,7 @@ export const CreateWalletDialog = ({ open, onOpenChange, section }: CreateWallet
               <div className="mt-4 flex items-start gap-2 rounded-lg border border-destructive/40 bg-destructive/5 p-3 text-xs">
                 <TriangleAlert className="mt-0.5 h-4 w-4 shrink-0 text-destructive" />
                 <span>
-                  <span className="font-medium">VAULT_STORE_KEY is not configured.</span> The sidecar refuses to store
+                  <span className="font-medium">The secret store is unreachable.</span> The sidecar refuses to store
                   wallet secrets without it, so creation is disabled until it is set.
                 </span>
               </div>