fix(org-switcher): give the create-organization icon button an accessible name

[pedrofrxncx]

The org switcher popover (apps/web/src/components/header/org-switcher.tsx, used by both the sidebar-footer account popover and the toolbar org breadcrumb) renders a + button that opens the create-organization dialog. It has no aria-label, no visible text, and no title — only a Plus icon glyph — so a screen reader announces it as an unlabeled button, and there's no accessible way for AT users to know it creates an organization.

Fix: add header.orgSwitcher.createOrganization ("Create organization" / "Criar organização") to the en/pt-br header dictionaries and wire it as the button's aria-label, matching the existing pattern used by every other icon-only control in the same file (e.g. the invitation-decline XClose button already has one).

How to verify: cd apps/web && bunx tsc --noEmit (clean on the touched files) and inspect the accessible name of the + button in the org switcher popover (org icon in the sidebar header or toolbar breadcrumb → click to open → the + icon button top-right of the search bar) — it now reads "Create organization" instead of being unlabeled.

Locally ran: bun run fmt, cd apps/web && bunx tsc --noEmit (no new errors — the one pre-existing prosemirror version-mismatch error is unrelated to these files), bunx oxlint on the three touched files (0 warnings/errors). No unit test added — this is a static aria-label fix with no branching logic to exercise; full CI covers the rest.

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Summary by cubic

Gives the create-organization button in the org switcher an accessible name so screen readers announce it as "Create organization" instead of an unlabeled button. Adds the label to the en and pt-br header dictionaries.

^{Written for commit 8ab36f0. Summary will update on new commits.}

[pedrofrxncx]

Closing as stale: this PR sat past the bot's 48h merge window, main has moved on, and its CI results no longer reflect the current base. This is a housekeeping close, not a rejection of the change — if the underlying problem still exists, the bot will find it again and open a fresh, rebased PR.

[studio-bot:stale-close]