Infra bindings + adapters (LOCK DO, Vectorize, R2, Browser, private-config home, queue)

[JSONbored]

Part of #983.

Context

gittensory's wrangler.jsonc binds only AI, D1 DB, the RateLimiter DO, the multiplexed JOBS queue (+gittensory-jobs-dlq), cron */30, and now UNIFIED_REVIEW_COMMENT:"false". reviewbot's live wrangler.jsonc additionally binds: R2 AUDIT, KV REVIEW_CONFIG (per-slug private rubric), Vectorize VECTORIZE (reviewbot-rag), Browser BROWSER, and a LOCK Durable Object (SubmissionLock, per-PR mutex). The unified comment itself needs NO new binding (D1+AI+Queue suffice). Each missing binding is added ONLY as the feature that needs it lands — a binding gap is a SILENT runtime throw in the Worker (not caught at typecheck if Env is loose). createCloudflareAdapters (the pass-through adapter factory) should wrap these so the same core runs self-host later.

Deliverables

• Add a LOCK Durable Object class (export SubmissionLock, per-PR mutex with TTL ~180s / renew ~60s) + binding + migration; only RateLimiter DO exists today.
• Add the Vectorize binding (VECTORIZE, bge-m3 / 1024-dim cosine) — gated behind the RAG feature (#wire-rag); fail-safe to no-context when absent.
• Add an R2 AUDIT binding OR decide to keep audit on D1 (gittensory audits to D1 today via recordAuditEvent); document the decision (large-blob/screenshot storage is the only reason to add R2).
• Add the Browser binding (BROWSER) for visual capture — gated behind the visual feature (#visual-capture).
• Decide a home for the private per-slug REVIEW_CONFIG: a new KV namespace (hosted) vs D1/.gittensory.yml (#private-config seam) — record the decision here, implement in the private-config issue.
• Decide REVIEW_QUEUE vs reusing the multiplexed JOBS queue with a new review JobMessage type (+ the existing gittensory-jobs-dlq); prefer reuse unless isolation is required.
• Wire createCloudflareAdapters so each new binding is consumed through the adapter seam, not dereferenced raw.

Acceptance criteria

• Each binding is added incrementally with the feature that needs it, never dereferenced before it exists; every new path is fail-safe-guarded when its binding is absent.
• A LOCK/SubmissionLock DO provides a per-PR concurrent-review mutex.
• The queue and private-config decisions are recorded (reuse JOBS vs new REVIEW_QUEUE; KV vs D1 for REVIEW_CONFIG).

Notes

• Milestone: M1
• Depends on: Native deep-review engine port — strategy + scaffold #1013
• Binding-gap silent failures: any ported path dereferencing env.REVIEW_CONFIG / VECTORIZE / AUDIT / BROWSER / LOCK throws at RUNTIME (not typecheck if Env is loose). Add the binding + a fail-safe guard before wiring each capability.