v0.8.0-alpha.6 - Merchant inventory insights UI

INV-03 adds the read-only merchant inventory insights experience.

Highlights:

• /merchant/ai-operations route and “AI 经营助手” navigation entry
• deterministic risk summary, filters, stable ordering, desktop table, and mobile cards
• lazy privacy-minimized evidence drawer with explicit rules, windows, calculation time, and limitations
• loading, timeout, permission, error, and empty states
• 64-bit-safe SKU identifiers plus component/API coverage

Safety boundary:

• no model or explain request on initial load or elsewhere in this release
• no automatic pricing, stock mutation, publish/unpublish, order, or refund action
• no deployment or production-data change

Validation:

• PR #73 CI: 14/14 successful
• main CI run 29733883336: 14/14 successful
• server Node 22 unit tests: 7 files / 19 tests
• TypeScript/Vite build and high-severity dependency audit passed
• desktop 1440×900 and mobile 390×844 browser checks passed

This remains a prerelease. INV-04 AI explanation and later stocktake/customer-service stages are not included.