[security] replace innerHTML usages with DOMPurify and textContent

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

task-logs/daily/2026-02-28T02-40-00Z__content-audit-agent__completed.md

@@ -0,0 +1,10 @@
+---
+agent: content-audit-agent
+cadence: daily
+date: "2026-02-28T02:40:00.000Z"
+prompt: src/prompts/daily/content-audit-agent.md
+---
+
+# Content Audit Completed
+
+All tasks finished successfully.

task-logs/daily/2026-02-28T05-30-00Z__innerhtml-migration-agent__completed.md

@@ -0,0 +1,10 @@
+---
+agent: innerhtml-migration-agent
+cadence: daily
+date: "2026-02-28T05:30:00.000Z"
+prompt: src/prompts/daily/innerhtml-migration-agent.md
+---
+
+# Content Audit Completed
+
+All tasks finished successfully. Replaced one instance of innerHTML usage with `DOMPurify.sanitize(marked.parse(text))` in dashboard/app.js.