fix(ui): replace pod CLI download link with GitHub releases link (#27805)

[KKamJi98]

The help page offered a single Linux binary served from the pod, which is the wrong binary for macOS, Windows and arm users and a surprise ~200MB download from the cluster.

Per the discussion in the issue, the button now links to the GitHub releases page for the running version instead: straight to the release tag when the server reports one (v3.4.1, v3.4.0-rc1), or the releases list for dev builds (v3.5.0+0dc5b3f).

Admins who want direct download buttons (internal mirrors, air-gapped clusters) can still configure them with the existing help.download.<os>-<arch> keys, and those can point at the binary the server keeps serving at download/argocd-linux-<arch>. Updated the operator docs to match.

Closes #27805

Checklist:

• Either (a) I've created an enhancement proposal and discussed it with the community, (b) this is a bug fix, or (c) this does not need to be in the release notes.
• The title of the PR states what changed and the related issues number (used for the release note).
• The title of the PR conforms to the Title of the PR
• I've included "Closes [ISSUE #]" or "Fixes [ISSUE #]" in the description to automatically close the associated issue.
• I've updated both the CLI and UI to expose my feature, or I plan to submit a second PR with them.
• Does this PR require documentation updates?
• I've updated documentation as required by this PR.
• I have signed off all my commits as required by DCO
• I have written unit and/or e2e tests for my change. PRs without these are unlikely to be merged.
• My build is green (troubleshooting builds).
• My new feature complies with the feature status guidelines.
• I have added a brief description of why this PR is necessary and/or what this PR solves.
• Optional. My organization is added to USERS.md.
• Optional. For bug fixes, I've indicated what older releases this fix should be cherry-picked into (this may or may not happen depending on risk/complexity).

[bunnyshell]

✅ Preview Environment deployed on Bunnyshell

Component	Endpoints
argocd	https://argocd-5oxoxz.bunnyenv.com/
argocd-ttyd	https://argocd-web-cli-5oxoxz.bunnyenv.com/

See: Environment Details | Pipeline Logs

Available commands (reply to this comment):

• 🔴 /bns:stop to stop the environment
• 🚀 /bns:deploy to redeploy the environment
• ❌ /bns:delete to remove the environment

[codecov]

Bundle Report

Changes will increase total bundle size by 153 bytes (0.0%) ⬆️. This is within the configured threshold ✅

Detailed changes

Bundle name	Size	Change
argo-cd-ui-array-push	10.67MB	153 bytes (0.0%) ⬆️

Affected Assets, Files, and Routes:

view changes for bundle: argo-cd-ui-array-push

Assets Changed:

Asset Name	Size Change	Total Size	Change (%)
main.*.js	153 bytes	3.46MB	0.0%

[kunalworldwide]

Clean PR. A few things I checked:

• Version regex ^v\d+\.\d+\.\d+(-[0-9A-Za-z.]+)?$ correctly matches release tags (v3.4.1) and pre-release (v3.4.0-rc1), while sending build metadata versions (+) to the generic releases list. Makes sense since + builds don't have GitHub release tags.
• External link correctly uses target='_blank' rel='noopener noreferrer'.
• Backward compat for air-gapped setups preserved — help.download.<os>-<arch> ConfigMap keys still work, and the server still serves its embedded binary at download/argocd-linux-<arch>.
• Test coverage is good — covers released versions, RC, dev builds, empty string, and undefined.
• Docs update removes the stale note about duplicate Linux buttons.

LGTM.