fix: resolve registry window for relay hosts via provider-prefixed key scan

[ranxianglei]

Closes the 64k window mismatch on relay hosts: registryLookup now scans provider-prefixed candidates when the host is unknown and the bare key misses (all matches must agree). Includes 5 tests incl. #282 regression.

Agent-prepared (branch pushed by ework-daemon via credhelper); PR opened via git credential API per AGENTS.md flow.

[github-actions]

📦 Built Package Artifact

Branch: 2026-08-27_registry-relay-fallback (fb6e044)

Option A — Install from npm PR tag (recommended)

npm install -g billion-context@pr-284

Each push to this PR publishes a new version under the pr-284 npm tag.

Option B — Download artifact

1. Download the artifact from the Actions run
2. Extract the tarball and install:

tar xzf billion-context-pr284.tgz
npm install -g package

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This comment is automatically updated on each push.

[ranxianglei]

[bot] Reviewed PR #284 (2026-08-27_registry-relay-fallback, 1 commit ahead of master, master fully contained).

Diff review — src/registry.ts:264-282 + tests/registry.test.ts (+5 tests):

• Fallback only fires when provider === undefined (unknown relay host or no host), so known-provider hosts keep the old strict behavior — a miss on api.minimax.chat still means unlisted, no cross-provider bleed.
• Scan is slash-bounded (key.endsWith("/" + model)), so "v4-flash" can't match "deepseek-v4-flash".
• Conflict rule verified: two provider-prefixed keys with different windows → undefined (falls back to the static table rather than guessing).
• peekRegistryContext/bundledSnapshotLookup/contextFromRegistry all route through registryLookup, so the fix covers warm cache, cold bundled snapshot, and the async path uniformly.

Pre-flight (run on the PR branch):

• npm run typecheck — clean
• npm test — 662/662 pass, incl. the 5 new registry tests (relay fallback, conflict no-guess, slash-bounded, known-provider no-scan, and the bili出现连续压缩情况 #282 bundled-snapshot regression: bundledSnapshotLookup("deepseek-v4-flash", "freeinference.org") → 1,000,000)
• npm run build — success

PR is open and ready. Per AGENTS.md, merging is human-only — please merge when ready: #284

_{🤖 ework agent · vllm-qwen/qwen3.8-27b}