fix(codex): polish accounts card overflow and weekly-only tray bar

[Finesssee]

Follow-up CUA proof pass on #260 caught two polish defects found post-merge (screenshots in proof-255260/):

1. Settings accounts card email overflow — at the fixed 720px window, a long account email (e.g. an Apple private-relay alias) in .credential-card__info strong paints OVER the 242px-wide 3-button actions row, and the "No usage data" text wraps word-by-word. Fix (styles.css, scoped to the .codex-accounts-card surface used by CodexAccountsSection):

• .codex-accounts-card .credential-card__info gets min-width: 0; overflow: hidden; text-overflow: ellipsis; white-space: nowrap
• .codex-accounts-card .credential-card__info strong gets max-width: 100% + ellipsis so the title ellipsizes and the buttons stay inside the card
• .codex-accounts-card .credential-card__actions gets flex-shrink: 0 + nowrap

2. Tray accounts menu bar absent — an account whose backend returns ONLY a weekly window (snapshot primaryWindow: null) rendered no usage bar while everything else worked. CodexAccountsMenu.tsx bar computation now prefers primaryWindow and falls back to the next filled window in canonical order (primary → secondary; the CodexAccountUsageSnapshot bridge type carries no tertiary or extra rate windows). No existing TS fallback pattern to copy — the ambient MenuCard builds independent rows per window; the canonical ordering mirrors the Rust tray metric order in tray_bridge.rs.

Tests (224 → 226):

• CodexAccountsMenu: renders a 42% bar from a weekly-only snapshot (primaryWindow null / secondaryWindow 42%)
• CodexAccountsSection: CSS rule assertion of the containment properties. Note: a DOM-level computed-style test is not possible — vitest runs jsdom with css: false, so styles.css is never applied; the test reads the stylesheet and asserts the exact containment rules instead.

Verified: tsc --noEmit, pnpm test (226 passing), pnpm run build.

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