[codex] redesign quota list display and watch diagnostics

[Dikevin]

What changed

• split Desktop runtime helpers into focused modules for runtime expressions, normalization, and signal parsing
• redesign codexm list around decision-making fields such as SCORE, ETA, NEXT RESET, summary rows, and standardized totals
• normalize displayed scores across plans, compact list presentation, and clarify reset/availability presentation for exhausted accounts
• improve watch history persistence and ETA estimation by segmenting continuous burn spans, isolating accounts, and persisting managed account identity
• add list --debug diagnostics for observed per-plan 5H:1W ratios and switch plan normalization to exact direct ratios
• sync internal design docs with the current list and watch behavior

Why

The branch grew beyond the original Desktop runtime helper split. It now also tightens the quota model and makes codexm list more useful as a switching dashboard, while making watch-based ETA and diagnostics more reliable.

Impact

User-visible changes are concentrated in codexm list and watch-based diagnostics. The refactor pieces remain structural; no intended semantic change outside the updated quota display, reset presentation, ETA/debug behavior, and related normalization rules.

Validation

• pnpm typecheck
• pnpm test