feat(gateway): P0-C SSE 流式转发 + 上游 key 加密 + 共享/钱包/交易 API (v0.2.2)

[argszero]

Summary

P0-C backend implementation (rant 2026-08-18T10:36:04 — SSE 流式转发 + 上游 key 加密 + 共享/钱包/交易 API). Completes streaming support (required by Cursor/Claude Code), upstream key encryption at rest, and user-facing sharing/wallet/transaction APIs aligned with the prototype. Version v0.2.2.

Changes

1. SSE streaming (src/gateway.rs)

• stream:true requests take a streaming path: reqwest bytes_stream passthrough chunk-by-chunk, keeping data:/event: lines verbatim
• Response headers content-type: text/event-stream + cache-control: no-cache
• Usage metering from stream tail: OpenAI last-chunk usage (with stream_options.include_usage), Anthropic message_start input_tokens + message_delta output_tokens
• Client disconnect aborts upstream (stream dropped → settle never runs → no charge)
• Initial-connection failover reuses the P0-B 7-rule routing (401/403/429/5xx/network → cooldown → switch, max 3)

2. Upstream key encryption (src/crypto.rs new)

• AES-256-GCM (RustCrypto aes-gcm), format v1:<nonce_hex>:<cipher_hex>
• Master key: env ATP_MASTER_KEY → config [server].master_key → dev random + warning
• Startup migration db::migrate_key_encryption: legacy plaintext keys auto-encrypted (idempotent)
• Gateway decrypts before forwarding; decrypt failure treats key as unhealthy

3. Sharing API (src/routes/sharing.rs new, prototype US-8/9)

• POST /api/sharings — list a key (encrypted at rest, DB never holds plaintext)
• GET /api/sharings — my sharings with masked key sk-****xxxx, used/quota/earn/status/available window
• PATCH /api/sharings/:id — pause/resume/soft-delete (paused/on/off)
• keys gains available_days/available_start/available_end/note columns (v2 migration, idempotent ensure_column)

4. Wallet / Transactions / Dashboard (src/routes/wallet.rs new)

• GET /api/wallet → {balance, month_use, month_earn}
• GET /api/transactions?type=&page=&page_size= — type filter (consume/earn/all), pagination, time desc
• GET /api/dashboard — month aggregation by type + net change + last-7-days series (sparkline)

Tests

• 49 tests pass (16 new: crypto 5, db migration 2, SSE/gateway 4, sharing 3, wallet 2)
• cargo build + cargo clippy --all-targets -- -D warnings + cargo fmt --check clean
• Live smoke: stream:true → SSE chunked with [DONE] + correct headers; DB keys all v1: ciphertext (incl. migrated placeholder); sharing list masked; wallet/transactions/dashboard ledger correct (consume + earn 90/10)

Notes

• Version bumped to v0.2.2
• Available-window enforcement deferred to P1 (stored & displayed only)

Closes rant 2026-08-18T10:36:04.876683 (P0-C).