feat: harden rotation behavior and dashboard controls

[jorgitin02]

Hello there!! I use this repo a lot a decided to make a few upgrades/changes. if you like them you can merge them into the main repo! thanks.

This update hardens account rotation behavior and dashboard controls for multi-account Codex usage:

• Accounts that hit rate limits are slept until reset instead of being retried immediately.
• Force Mode is strict (no silent fallback to another alias when force is active).
• Rotation strategy control is visible next to Force Mode in dashboard.
• Runtime account selection now follows persisted dashboard strategy changes reliably.
• Dashboard now explains Force Mode and strategy behavior via mouseover help.
• Enabled/disabled account toggles are enforced in rotation eligibility.

Why this matters

• Reduces wasted retries on exhausted accounts.
• Makes forced-account testing deterministic.
• Prevents confusion where UI setting changed but runtime behavior did not.
• Improves operator clarity during live testing.

Key behavior changes

1. Limit sleep until reset

• On 429, code computes rateLimitedUntil from:
  • Retry-After
  • known rate-limit window reset times
  • provider reset text in error message
  • fallback cooldown
• Rotator excludes any account with rateLimitedUntil > now.

2. Force Mode strict pinning

• When Force Mode is active, requests only target the forced alias.
• If forced alias is blocked (for example rate-limited), request fails with deterministic error instead of falling back.
• Force state auto-clears only on expiry/removal/disabled account, not transient ineligibility.

3. Runtime strategy reliability

• Rotation reads runtime settings used by dashboard persistence.
• Strategy updates from /api/settings apply to selection logic immediately.
• Legacy strategy field is kept in sync for compatibility with force-state restore.

4. Dashboard UX improvements

• Strategy selector appears next to Force Mode.
• Hover/mouseover help explains each strategy and Force Mode interaction.
• Weighted round-robin tooltip now explains percentage behavior with example and skip rules.

Compatibility and risk

• Backward compatible for existing stores.
• No destructive migrations introduced in this patch set.
• Main risk area is strategy precedence across env overrides vs persisted settings; this update makes runtime behavior deterministic from persisted settings for dashboard operations.

Verification executed

Run locally in repo root:

npm run lint
npm run test:unit
npm run build

Latest observed results:

• lint: pass
• test:unit: pass (9 suites, 125 tests)
• build: pass

Live checks performed against local dashboard (127.0.0.1:3434):

• Strategy toggle reflected in /api/state and restored successfully.
• New tooltip strings confirmed in served dist/web.js.

Recommended reviewer focus

1. src/index.ts and src/rate-limits.ts: 429 handling and reset inference.
2. src/rotation.ts and src/force-mode.ts: strict force semantics and runtime strategy path.
3. src/settings.ts: runtime settings precedence and sync semantics.
4. src/web.ts: strategy/force UI placement and tooltip copy.