fix(frame): render continuous box borders

[kitlangton]

What

Render light Unicode box-drawing characters as continuous pixel geometry in Drive's shared frame renderer. Captured OpenCode Mermaid diagrams now have uniform borders in both PNG exports and the browser catalog.

Before / After

Before: light box characters fell through to font rendering, leaving row-boundary gaps. Drawing connected segments geometrically initially exposed a second issue: overlapping translucent rectangles accumulated alpha at cell centers and junctions, producing periodic bright dashes and hotspots.

After: each box glyph paints a non-overlapping union of integer-aligned rectangles. Adjacent cells meet edge-to-edge, while every pixel inside a glyph is painted at most once.

How

• packages/drive/src/frame/index.ts recognizes light lines, corners, rounded corners, tees, and crossings as shared geometric primitives.
• packages/drive/test/frame.test.ts verifies integer alignment and rejects overlapping pixel coverage.
• @opencode-ai/client is updated from next-16543 to next-17010; the manual interleaving fixture follows the canonical callID to id protocol rename.
• A patch changeset records the published renderer fix.

Scope

This does not change OpenCode's native Mermaid generation or the standalone Merman package. It only changes how OpenCode Drive renders captured terminal frames.

Testing

• bun run --cwd packages/drive test:effect (205 tests)
• bun run --cwd packages/drive typecheck
• bun run --cwd packages/drive lint
• bun run --cwd apps/catalog typecheck
• bun run --cwd apps/catalog test (28 tests)
• bun run --cwd apps/catalog build

Demo

This is a real Drive PNG render of dim, translucent box glyphs before and after the fix, enlarged with nearest-neighbor scaling so individual terminal pixels remain visible.