Deprecate and add lint rule to limit the usage of daysSinceInstalled

[YoussefKeyrouz]

Task/Issue URL: https://app.asana.com/1/137249556945/project/1212810093780571/task/1213839965185097?focus=true

Description

This PR deprecates UserBrowserProperties.daysSinceInstalled() and add Lint rule to limit future usage (with baseline for current usages)

TLDR
UserBrowserProperties.daysSinceInstalled() is a less reliable implementation of the existing PackageInfo.firstInstallTime and PackageInfo.lastUpdateTime. It introduces a race condition that might break the logic if used on startup coroutines (e.g. if called from RealDuckChat.cacheUserSettings()). So it’s better and more reliable to use the existing time android provides, or APIs that leverage those values such as AppBuildConfig.isNewInstall()

Steps to test this PR (Optional, Can only be tested via code pull)

• Pull the changes on the branch
• Manually call UserBrowserProperties.daysSinceInstalled() from anywhere
• verify lint fails
• Line does not fail for existing usage

---

Note

Low Risk
Low risk: changes are limited to deprecating an API and adding a lint check with a baseline to prevent new call sites, with no runtime behavior changes unless callers migrate.

Overview
Deprecates UserBrowserProperties.daysSinceInstalled() and steers callers toward more reliable install-time APIs.

Adds a custom lint rule that flags new usages of daysSinceInstalled() while allowing existing usages via a baseline, preventing further adoption without breaking current builds.

^{Written by Cursor Bugbot for commit 4ada182. This will update automatically on new commits. Configure here.}

[YoussefKeyrouz]

• Deprecate and add lint rule to limit the usage of daysSinceInstalled #8136 👈 (View in Graphite)
• develop

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[aitorvs]

lgtm. Thanks for doing this