TF-2533 Add ADR on memory leak js lifecycle

docs/adr/0045-memory-leak-with-js-lifecycle.md

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+# 44. Memory leak with js lifecycle
+
+Date: 2024-04-09
+
+## Status
+
+Accepted
+
+## Context
+
+- The js resources are disposed at the end of js lifecycle
+- Current listener in used is `beforeunload`. However, `beforeunload` was unstable, resulting in memory leak.
+
+## Decision
+
+- `beforeunload` was replaced by `pagehide`, which is more reliable.
+  - [`pagehide` documentation](https://developer.mozilla.org/en-US/docs/Web/API/Window/pagehide_event)
+  - [Google Chrome recommendation](https://developer.chrome.com/docs/web-platform/page-lifecycle-api#the_unload_event)
+## Consequences
+
+- Memory leak problem in composer on TMail is resolved.