Track multiple subscription plans simultaneously (Claude + Codex)

[SPACEMAN1898]

Feature request: track multiple subscription plans simultaneously

Current behaviour

codeburn plan set accepts a single plan with a --provider scope (claude / codex / cursor / all). Setting a Codex plan overwrites the previously-set Claude plan, so only one provider's overage line ("X.Yx your subscription value", "vs A$X plan" bar) is shown at a time.

Use case

I'm subscribed to both Claude Max 20x ($200/mo) and ChatGPT Pro ($200/mo, tracked as codex provider in codeburn). I want the dashboard to show overage tracking for both plans concurrently — same way it already shows cost/calls/sessions for both providers in the unified report.

Suggested shape

Two ergonomic options:

1. Multi-plan config: plan becomes plans (array or provider-keyed map) in ~/.config/codeburn/config.json. Existing plan key kept as a single-plan shortcut for back-compat.

   "plans": {
     "claude": { "id": "claude-max", "monthlyUsd": 200, "resetDay": 1 },
     "codex":  { "id": "custom",     "monthlyUsd": 200, "resetDay": 1 }
   }

2. Per-provider plan set: codeburn plan set claude-max --provider claude and codeburn plan set custom --provider codex --monthly-usd 200 would each append/replace only the plan for that provider, instead of replacing the whole plan object.

Report impact

The 7-day / 30-day summary card would render one overage line per active plan (or stack them):

Claude Max 20x: A$4066 API-equiv vs A$276 plan  14.7x — projected month A$11,193
ChatGPT Pro:    A$xxx  API-equiv vs A$276 plan  Y.Yx — projected month A$xxx

Why this matters

For users on both top-tier plans (increasingly common), the overage view is the most actionable part of the dashboard — but it currently forces a choice. Without multi-plan, I have to swap plans manually to compare overage on each.

Happy to take a stab at a PR if the shape is acceptable. Could you signal preferred direction (multi-plan map vs. per-provider set commands) before I start?

[ozymandiashh]

Opened PR #300 for this: #300

The implementation uses the provider-keyed config shape suggested here while keeping the existing single-plan plan key as a backward-compatible fallback.

Example new config shape:

{
  "plans": {
    "claude": { "id": "claude-max", "monthlyUsd": 200, "resetDay": 1 },
    "codex":  { "id": "custom", "monthlyUsd": 200, "resetDay": 1 }
  }
}

What changed:

• codeburn plan set claude-max and codeburn plan set custom --monthly-usd 200 --provider codex can now coexist.
• codeburn plan reset --provider codex removes only the Codex plan; plain codeburn plan reset still clears all plan config.
• dashboard overview renders one overage row per active provider plan.
• JSON outputs keep the legacy top-level plan field and add a provider-keyed plans map for multi-plan consumers.
• aggregate all plans are kept mutually exclusive with provider-specific plans to avoid double-counted overage rows.
• hand-edited configs containing both plans.all and provider-specific plans are normalized defensively on read.

Validation run:

• npm run build
• npx vitest run - 47 files / 673 tests passing
• git diff --check
• external review with Claude Opus 4.7 effort max: PASS
• external review with Gemini 3.1 Pro Preview: PASS

One note: npx tsc --noEmit still fails on an existing unrelated src/models-report.ts type error outside this PR's diff.