chore(settings): move Account tab to the top, drop duplicate local-data footer

[graydawnc]

What

Two small Settings-panel cleanups ahead of the share launch:

• Account tab now leads the sidebar rail. It was pinned to the bottom to avoid tab-shift when the sharePublish flag flips, but the flag is build-time (Vite-inlined), so the rail can never shift within a running session — the rationale no longer applies. With sign-in becoming a first-class part of the app, identity belongs at the top. The tab is still hidden in builds without VITE_FEATURE_SHAREPUBLISH=1.
• Removed the sidebar footer ("All data stays local in ~/.spool/"). It duplicated the General → Data section, which already shows the database path. The settings.localData_footer key is removed from all 7 locales to keep key parity.

How

• TAB_DEFS reordered; the FooterPath component and its only call site deleted.
• Tab buttons gained data-testid="settings-tab-<id>" so tests can address tabs without text-matching (per the e2e selector discipline).

Test plan

• New e2e in settings.spec.ts: first rail entry is settings-tab-account, and the sidebar no longer contains the ~/.spool/ footer probe (locale-independent).
• App unit suite: 482 passed (includes locale key-parity).
• e2e: settings.spec.ts + full share-publish.spec.ts (Account-tab flow) green locally.

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