perf: visibility-gate dashboard render loop

Co-authored-by: PR0M3TH3AN <[email protected]>

src/context/CONTEXT_2026-02-16.md

@@ -0,0 +1,19 @@
+# Context: perf-agent (2026-02-16)
+
+## Goal
+Improve app responsiveness by finding and fixing background CPU/network work.
+
+## Scope
+- Focus on "Visibility gating" for `dashboard/index.html`.
+- Run grep searches for performance patterns.
+- Ensure `INITIAL_BASELINE.md` exists.
+
+## Constraints
+- Minimal changes.
+- Safe changes only.
+- No network access to external sites.
+- Running as a simulated agent (Jules).
+
+## Assumptions
+- `dashboard/index.html` is the primary entry point for the dashboard.
+- `setInterval` in `dashboard/index.html` runs even when tab is hidden, wasting CPU.