v1.2.0 — OpenCode v2 image and PDF bridge

OpenCode v2 production release for automatic image and PDF understanding in text-only sessions. Defaults to zai-coding-plan/glm-5.3-flash; adds capability-aware image bridging, bounded PDF-to-PNG rendering with bundled font/CMap/WASM assets, per-attachment fail-soft behavior, strict project-scoped read_image handling, bounded retryable caching, idempotent media injection, reusable internal sessions, project-scoped digest storage, multilingual documentation, and a loadable root package entrypoint. Verified with 60 passing tests plus live OpenCode v2 image and PDF flows. Grok's final passive adversarial review returned SHIP.