Set up project scaffold: Bun/OpenCode plugin with registry pattern

- AGENTS.md adapted from taskgraph for this Bun/TypeScript plugin
- Dual MIT/Apache-2.0 licenses
- Package.json, tsconfig, biome config following open-memory pattern
- Skeleton src/ with registry-pattern tasks tool (help operation working)
- Opencode.json plugin config
- .gitignore for dist, node_modules, lockb
- Remove typo .gitingore files, proper .gitignore in .opencode/

.opencode/.gitingore

@@ -1,4 +0,0 @@
-node_modules
-package.json
-bun.lock
-.gitignore

.opencode/agents/.gitingore

@@ -1,4 +0,0 @@
-node_modules
-package.json
-bun.lock
-.gitignore