fix(dashboard): show lifetime cache impact after restart

Author: JerrettDavis

headroom/dashboard/templates/dashboard.html

@@ -469,7 +469,7 @@ <h3 class="mb-3 text-sm font-medium text-gray-300">Live Activity</h3>
                 </div>
 
                 <!-- Prefix Cache Impact: current process only -->
-                <template x-if="cacheSessionActive">
+                <template x-if="hasPrefixCacheImpact">
                     <div class="bg-surface rounded-lg p-4 border border-border mb-6">
                         <div class="flex justify-between items-center mb-3">
                             <div class="text-sm font-medium text-gray-300">Prefix Cache Impact</div>
@@ -516,6 +516,13 @@ <h3 class="mb-3 text-sm font-medium text-gray-300">Live Activity</h3>
                                 <div class="text-xs text-gray-500" x-show="!cacheSessionActive">no activity since restart</div>
                             </div>
                         </div>
+                        <template x-if="lifetimeCacheReadTokens > 0 || lifetimeCacheSavingsUsd > 0">
+                            <div class="rounded-lg border border-emerald-500/20 bg-emerald-500/5 p-3 mb-4">
+                                <div class="text-xs text-gray-500 uppercase tracking-wide mb-1">Cache Reads (lifetime)</div>
+                                <div class="text-2xl font-light tabular-nums text-emerald-400" x-text="formatNumber(lifetimeCacheReadTokens)"></div>
+                                <div class="text-xs text-emerald-400/70" x-text="'$' + formatCurrency(lifetimeCacheSavingsUsd) + ' saved'"></div>
+                            </div>
+                        </template>
                         <!-- Cache efficiency bar (session-scoped; hidden until traffic arrives) -->
                         <div x-show="cacheSessionActive">
                             <div class="flex justify-between text-xs text-gray-500 mb-1">
@@ -2478,6 +2485,20 @@ <h3 class="mb-3 text-sm font-medium text-gray-300">Live Activity</h3>
                     return (this.stats.prefix_cache?.totals?.requests || 0) > 0;
                 },
 
+                get lifetimeCacheReadTokens() {
+                    return this.stats.persistent_savings?.lifetime?.cache_read_tokens || 0;
+                },
+
+                get lifetimeCacheSavingsUsd() {
+                    return this.stats.persistent_savings?.lifetime?.cache_savings_usd || 0;
+                },
+
+                get hasPrefixCacheImpact() {
+                    return this.cacheSessionActive
+                        || this.lifetimeCacheReadTokens > 0
+                        || this.lifetimeCacheSavingsUsd > 0;
+                },
+
                 get cacheSavingsPercent() {
                     const t = this.stats.prefix_cache?.totals || {};
                     const total = (t.cache_read_tokens || 0) + (t.cache_write_tokens || 0);

tests/test_dashboard_cache_ttl_playwright.py

@@ -194,26 +194,32 @@ def test_dashboard_per_project_setup_url_uses_current_origin() -> None:
         _install_dashboard_routes(page)
 
         page.goto("http://127.0.0.1:8788/dashboard", wait_until="load")
+        page.get_by_role("button", name="Lifetime").click()
         expect(
             page.get_by_text(
-                "ANTHROPIC_BASE_URL: http://127.0.0.1:8788/p/<project-name>", exact=True
+                "Route project traffic through http://127.0.0.1:8788/p/<project-name>",
+                exact=True,
             )
         ).to_be_visible()
         expect(
             page.get_by_text(
-                "ANTHROPIC_BASE_URL: http://127.0.0.1:8787/p/<project-name>", exact=True
+                "Route project traffic through http://127.0.0.1:8787/p/<project-name>",
+                exact=True,
             )
         ).to_have_count(0)
 
         page.goto("http://headroom.local:9393/dashboard", wait_until="load")
+        page.get_by_role("button", name="Lifetime").click()
         expect(
             page.get_by_text(
-                "ANTHROPIC_BASE_URL: http://headroom.local:9393/p/<project-name>", exact=True
+                "Route project traffic through http://headroom.local:9393/p/<project-name>",
+                exact=True,
             )
         ).to_be_visible()
         expect(
             page.get_by_text(
-                "ANTHROPIC_BASE_URL: http://127.0.0.1:8787/p/<project-name>", exact=True
+                "Route project traffic through http://127.0.0.1:8787/p/<project-name>",
+                exact=True,
             )
         ).to_have_count(0)