feat(core): reconcile conflicting financial facts

[13pgpg]

Summary

• add provider-neutral financial fact reconciliation states
• enforce period, currency, unit, and adjustment comparability
• collect all supporting provider results for audit and reconciliation flows
• expose financial report candidates with provider provenance
• keep this PR scoped to the reconciliation slice of Issue [Finance Data] Reconcile conflicting values across financial data providers #26

Refs #26

Validation

• OS: macOS Darwin 24.6.0 x86_64
• Bun: 1.4.2
• bun test packages/core/src/reconciliation.test.ts packages/shared/src/providers/reconciliation.test.ts packages/shared/src/providers/providers.test.ts: 35 passed, 0 failed
• bun run typecheck: core, i18n, shared, ui, and electron passed
• Coverage includes provider conflict, semantic mismatch, within-tolerance agreement, insufficient sources, and explicit provider priority without averaging
• No skipped tests; no Actions run was available for this head, so the local commands above are the verification evidence.

[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。

[13pgpg]

Implemented the next Issue #26 slice in commit 93a018d: ProviderRouter.executeAll now collects every supporting provider result, financial report candidate fetchers preserve provenance, and provider reconciliation fixtures cover exact agreement, material conflict, and insufficient sources. Tests: 26 passing; workspace typecheck passes.

[helsome]

93a018d 这一轮已经把 #26 的核心 reconciliation 切片推进了：executeAll 收集多 provider 候选、保留 provenance，规则能区分 agreement / within-tolerance / material-conflict / incomparable / insufficient，并且不静默平均。这个增量本身值得保留，但旧 REQUEST_CHANGES 还不能解除，且无需把整条 #26 都做完：

1. 当前 PR 仍写 Closes #26，但 diff 还没有完成该 Issue 明确要求的 Agent/report 显式表达冲突与 UI/evidence 查看候选来源。建议直接把范围收窄为 Refs #26 / Part of #26，父 Issue 保持开放；不要求本 PR 扩 UI。
2. 验证报告仍缺 OS 和明确 pass/fail/skipped；现有 focused tests 也没有看到“显式 providerPriority 选择且不平均”的回归用例，请补这一条即可。
3. GitHub 当前 mergeable=false，且本 head 没有 Actions run；更新到当前 main 时请一并处理冲突，并让与本 reconciliation slice 无关的 bun.lock 大幅漂移自然消失，或说明它为何确有必要。

完成以上最小项后即可重新审。

[13pgpg]

Addressed the review items in the rebased head (74d234f):

• narrowed the PR to the reconciliation slice and changed the description to Refs #26;
• rebased onto current upstream/main and removed unrelated bun.lock drift;
• added explicit providerPriority selection coverage proving no averaging;
• validation: macOS Darwin 24.6.0 x86_64, Bun 1.4.2, 35 passed / 0 failed, no skipped tests; core, i18n, shared, ui, and electron typecheck passed.

当前 head 74d234f 已补齐该 review 的测试证据：macOS Darwin 24.6.0 x86_64 / Bun 1.4.2、35 passed / 0 failed / 0 skipped、显式 providerPriority 且不平均的回归覆盖，并将范围收窄为 Refs #26。原 blocker 已过期。