docs+web: surface @nexudotio X account in README + entry sidebar

[Tuola-waj]

What this PR does

Surfaces the official X account @nexudotio in three places so visitors can subscribe to release notes and milestone threads in one click:

1. README header badge — adds an X follow badge next to Discord (same flat-square style).
2. README "Stay in the loop" section — a 2-sentence section right above Star us distinguishing the channels: Discord is for chat, X is for the milestones.
3. Web app entry sidebar — adds a Follow @nexudotio pill to entry-side-foot (same .foot-pill style as the existing Pet / Settings / Language pills). Opens X in a new tab with rel="noreferrer noopener".

Why now

• We're approaching 30K stars and posting milestone threads + release notes on X (@nexudotio). Currently neither the README nor the desktop client links to that channel — people who star the repo or install the app have no easy way to follow the project on socials.
• Discord is great for live conversation but doesn't surface release-style updates well. Having both channels discoverable lets each one do what it's good at.

Implementation notes

• README: 5 lines added, 0 removed.
• Web app: reuses the existing .foot-pill CSS (already supports <a> with text-decoration: none) and the existing external-link Icon — no new CSS, no new icon, no new i18n key required (single short English label, consistent with how the other foot pills are minimalist).
• 2 commits, 16 lines added total, only README.md and apps/web/src/components/EntryView.tsx touched.

What is not changed

• No content removed or reordered.
• No copy edits to other sections.
• No new images or assets — README badge uses shields.io like the rest of the header.

[mrcfps]

@Tuola-waj I reviewed the README-only changes: the new X badge matches the existing header badge pattern, points to the official @nexudotio profile, and the new “Stay in the loop” copy cleanly distinguishes X milestones from Discord chat. I did not find any actionable correctness, safety, test, or maintainability issues in the changed ranges. Thanks for keeping the docs update focused and easy to review 🙌

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[mrcfps]

@Tuola-waj I reviewed the updated README badge/"Stay in the loop" copy and the new entry-sidebar Follow @nexudotio pill. The web link reuses the existing foot-pill styling, opens X in a new tab with the expected noreferrer/noopener protection, and the README additions fit the existing badge/section structure. I also checked the current failing workspace check; it is in existing e2e localized content coverage for social-media-dashboard and is outside these changed ranges. No actionable correctness, safety, test, or maintainability issues found in this PR head. Thanks for the focused follow-channel update 🙌

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