- Export adapter (src/adapters/opencode.ts): generates .opencode/instructions.md
  and opencode.json with provider/model config from agent.yaml
- Runner (src/runners/opencode.ts): creates temp workspace with instructions +
  config, launches `opencode` CLI in interactive or single-shot mode
- Import (src/commands/import.ts): reads .opencode/instructions.md + opencode.json,
  produces agent.yaml, SOUL.md, and RULES.md
- Git runner auto-detection: detects .opencode/ or opencode.json and routes to
  the opencode adapter
- Wired into export, run, and import commands with updated help text and README

Co-Authored-By: Claude Opus 4.6 (1M context) <[email protected]>

- Use AGENTS.md instead of .opencode/instructions.md (per OpenCode docs)
- Fix opencode.json config: model uses provider/model format, provider is object with npm package
- Fix runner CLI: use `opencode run --prompt` for single-shot mode
- Fix process.exit() before finally cleanup — move cleanup before exit
- Extract shared buildComplianceSection to src/adapters/shared.ts (dedup from copilot.ts)
- Fix importer to read AGENTS.md and parse provider/model format
- Fix git auto-detection to check opencode.json instead of .opencode/

Co-Authored-By: Claude Opus 4.6 (1M context) <[email protected]>