feat(core): reconcile conflicting financial facts

[13pgpg]

Summary

• add provider-neutral financial fact reconciliation states
• enforce semantic comparability before comparison
• preserve candidates and select by explicit provider priority without averaging
• add reproducible tests for conflict, mismatch, and tolerance cases

Refs #26

Validation

• Tests could not run because Bun is not installed in the current environment.

[13pgpg]

Validation update: installed Bun 1.4.2. Reconciliation tests pass (3/3), and workspace typecheck passes for core, i18n, and shared.

[helsome]

当前先卡测试证据，不扩大实现 scope。金融事实 reconciliation 属数据正确性路径，PR 不能以“环境没有 Bun”作为正式验收结果。请补一份可复现测试报告：Bun 版本 + OS、实际执行命令、pass/fail 数量；至少覆盖 provider 冲突、语义不可比、容差内一致、显式 provider priority 且不做平均这几条核心行为。若本机没有 Bun，可用项目固定的 Bun 1.4.2 或 npx --yes bun 执行。无需接真实 provider，这层确定性 reconciliation 用 focused test 即可证明。