fix(security): /api/usage default scope = self; admin all-keys requires ?all=true (#88)

Identified during privacy/security audit (.claude/research/ocp-security-audit.md
§3 "/api/usage 全量泄露所有 key 时序"). Previously, any caller authenticated as
admin received the full per-key usage byKey + recent + timeline block, which
means a brief admin-token compromise exposes every household member's request
volume, timing, and which-model — metadata, but sensitive metadata.

This is a deliberate breaking change for least-privilege.

Behavior matrix (post-change):

  Caller                                  | Default scope     | ?all=true
  ----------------------------------------|-------------------|---------------------
  anonymous (PROXY_ANONYMOUS_KEY)         | own ("anonymous") | ignored (still own)
  authenticated non-admin key             | own (key.name)    | ignored (still own)
  admin (no flag)                         | own ("admin")     | n/a
  admin with ?all=true                    | n/a               | full byKey/recent
  localhost-no-token / "local"            | own ("local")     | full (isAdmin=true)

Response shape is unchanged except for an additional advisory `scope` object
(`{self, all}`); existing fields keep their structure so dashboards and scripts
continue to parse cleanly — they just see less data unless they opt in.

Audit-friendly addition: when admin opts into `?all=true`, the server now
emits `logEvent("info", "admin_usage_full_scope", { caller, ip })` so every
privilege-escalation moment is recorded.

Backward-compat warning for admin scripts:
existing cron jobs / scripts that call `/api/usage` to inventory all keys must
add `?all=true` after this change. Default-self is the new safe behavior.

Dashboard (dashboard.html): adds a "Show all keys" checkbox in the Usage by
Key section. Hidden by default; revealed only when refreshKeys() succeeds
(same admin gate as the keys-management section). Toggle state persists in
localStorage as `ocp_usage_show_all`.

cli.js citation
---------------
This is OCP-internal admin API behavior — there is no `cli.js` operation to
cite. ALIGNMENT.md Rule 2 (the rule that limits OCP to operations that exist
in `cli.js`) does not constrain access-control rules for the OCP server's
own admin endpoints.

Smoke test (isolated test server on :3489, prod :3478 untouched):
- node --check server.mjs       SYNTAX_OK
- npm test                      43/43 passed
- alignment.yml blacklist grep  BLACKLIST_CLEAR
- LAN scope matrix              alice/bob own only; alice ?all=true denied;
                                anon ?all=true denied; admin all=true full +
                                audit log emitted

Iron Rule 10
------------
Author cannot self-approve. A separate fresh-context reviewer must read the
diff and confirm the cli.js-not-applicable statement is correct before merge.

Co-authored-by: dtzp555 <dtzp555@gmail.com>
Co-authored-by: Claude Opus 4.7 <noreply@anthropic.com>

dashboard.html

@@ -55,7 +55,13 @@
 </div>
 
 <div class="section">
-  <h2>Usage by Key</h2>
+  <div class="flex" style="justify-content: space-between; align-items: center;">
+    <h2 style="margin: 0;">Usage by Key</h2>
+    <label id="usage-scope-toggle" class="flex" style="display:none; gap: 0.4rem; font-size: 0.8rem; color: #94a3b8; cursor: pointer;">
+      <input type="checkbox" id="usage-show-all" style="cursor: pointer;">
+      <span>Show all keys</span>
+    </label>
+  </div>
   <table id="key-usage-table">
     <thead><tr><th>Key</th><th>Requests</th><th>OK</th><th>Err</th><th>Avg Time</th><th>Last Request</th></tr></thead>
     <tbody></tbody>
@@ -170,7 +176,8 @@ async function refreshStatus() {
 
 async function refreshUsage() {
   try {
-    const data = await api("/api/usage");
+    const showAll = localStorage.getItem("ocp_usage_show_all") === "1";
+    const data = await api(showAll ? "/api/usage?all=true" : "/api/usage");
     const tbody = document.querySelector("#key-usage-table tbody");
     tbody.innerHTML = (data.byKey || []).map(k => `
       <tr>
@@ -204,6 +211,8 @@ async function refreshKeys() {
   try {
     const data = await api("/api/keys");
     document.getElementById("key-mgmt-section").style.display = "";
+    // Admin-only "Show all keys" toggle for /api/usage scope.
+    document.getElementById("usage-scope-toggle").style.display = "flex";
     const tbody = document.querySelector("#keys-table tbody");
     tbody.innerHTML = (data.keys || []).map(k => `
       <tr>
@@ -240,6 +249,16 @@ async function refreshAll() {
   document.getElementById("refresh-indicator").textContent = `Updated ${new Date().toLocaleTimeString()}`;
 }
 
+// Wire "Show all keys" toggle (visibility gated to admin via refreshKeys()).
+(function setupUsageScopeToggle() {
+  const cb = document.getElementById("usage-show-all");
+  cb.checked = localStorage.getItem("ocp_usage_show_all") === "1";
+  cb.addEventListener("change", () => {
+    localStorage.setItem("ocp_usage_show_all", cb.checked ? "1" : "0");
+    refreshUsage();
+  });
+})();
+
 refreshAll();
 setInterval(refreshAll, 30000);
 </script>