Fix missing Claude Fable/Mythos 5 pricing

[pitimon]

Problem

claude-fable-5 usage appears in the TokenTracker model breakdown with token counts, but cost is blank/zero because the bundled pricing data does not yet provide a resolved price for the model.

A local report showed examples like:

• claude-fable-5 with millions of tokens but no displayed cost
• claude-sonnet-4-6 and claude-haiku-4-5-20251001 displaying costs correctly

Scope

Add pinned pricing for Claude Fable/Mythos 5 across the local pricing engine and dashboard edge pricing copies so local and cloud/account views compute cost consistently.

Acceptance

• claude-fable-5 resolves non-zero pricing.
• claude-mythos-5 resolves the same pinned tier for consistency.
• Model breakdown/account summaries compute costs for these model names and aliases.
• Pricing tests cover the pinned models and a representative cost calculation.
• Published package @ipv9/tokentracker-cli@0.39.12 includes the fix.

Validation already run

• node --test test/pricing.test.js
• node --test test/model-breakdown.test.js test/local-api-legacy-codex-schema.test.js test/local-api-source-scope.test.js
• node scripts/ops/validate-ui-hardcode.cjs
• npm --prefix dashboard run build
• npm --prefix dashboard test
• npm pack --dry-run --json
• local service smoke at http://127.0.0.1:7680/dashboard

[pitimon]

Opened draft PR #8 for the already-published pricing fix: #8

Published package: @ipv9/tokentracker-cli@0.39.12

Current validation on the PR branch:

• node --test test/pricing.test.js passed 33/33
• node scripts/ops/validate-ui-hardcode.cjs passed

The PR is stacked on #6 so its diff stays scoped to the Claude Fable/Mythos pricing change instead of pulling in the earlier dashboard rollover branch history.

[pitimon]

Completed in PR #8 and merged into branch fix/dashboard-midnight-rollover-preflight.

Published package: @ipv9/tokentracker-cli@0.39.12

Validation after rebasing onto the latest stacked base:

• node --test test/pricing.test.js
• node scripts/ops/validate-ui-hardcode.cjs
• git diff --check

Merge commit: 9d8199c4beca07ac13dc0a5135f89d024bea5425