chore: check move codgpkg to pkg fix imports and CI

- Update AGENTS.md, go.yml

Generated with Codg
Assisted-by: claude-opus-5-5 via Codg <codg@atomai.cc>

Author: vcaesar

.github/workflows/go.yml

@@ -29,5 +29,9 @@ jobs:
       - name: Build
         run: go build -v ./...
       - name: Test
-        run: go test -v ./plugin ./scripts
+        run: go test -v ./scripts
+      # plugin/ is a separate module (plugin/go.mod).
+      - name: Test plugin
+        working-directory: plugin
+        run: go vet ./... && go test -v ./...
         # run: go test -v .

AGENTS.md

@@ -0,0 +1,99 @@
+# AGENTS.md — Codg Plugin System
+
+Guide for AI agents working in `github.com/vcaesar/codg`.
+
+## Overview
+
+Codg is an AI coding assistant (CLI). This repo is the **plugin system** — hook-based architecture for extending Codg. Inspired by [opencode](https://github.com/anomalyco/opencode/tree/dev/packages/plugin). **Module**: `github.com/vcaesar/codg` · **Go**: 1.26.2 · **Tests**: [testify](https://github.com/stretchr/testify) `require` (only external dep).
+
+## Commands
+
+```bash
+cd plugin && go test ./...                      # all tests (plugin/ is its own module)
+cd plugin && go test -v ./demo/                 # single package
+cd plugin/auth/gemini/standalone && go build -buildmode=plugin -o ~/.codg/plugins/gemini-auth.so .
+```
+
+No Makefile or linter config. CI: `.github/workflows/go.yml`.
+
+## Layout (STANDALONE — no internal deps)
+
+```
+plugin/            # own module (plugin/go.mod); plugin.go (core), types.go (syncMap/eventBus/PermissionService), plugin_test.go (~1200 lines)
+├── pkg/           # package codgpkg — shared types: AgentTool, ToolInfo, ProviderOptions
+├── auth/          # gemini, claude (+ standalone/ for .so); codex/gpt stubs
+├── demo/          # hello tool + ShellEnv + SystemPrompt hooks
+├── enhancer/      # tool interception, message transform, error handling
+└── oauthplugin/   # OAuth tokens, provider resolution
+```
+
+## Key Interfaces
+
+```go
+type Plugin interface { Init(ctx context.Context, input PluginInput) (*Hooks, error) }
+type AgentTool interface {                      // plugin/pkg (codgpkg)
+    Info() ToolInfo
+    Run(ctx context.Context, params ToolCall) (ToolResponse, error)
+    ProviderOptions() ProviderOptions
+    SetProviderOptions(opts ProviderOptions)
+}
+type PermissionService interface { Request(ctx context.Context, opts PermissionRequest) (bool, error) }
+type PluginMetaProvider interface { Meta() PluginMeta }
+```
+
+## Hooks
+
+Signature: `(input ReadOnly, output *Mutable) error`. Plugins chain by mutating output, ordered by `Priority` (lower first; default 0). All optional.
+- **Short-circuit** on `output.Handled = true`: `OAuthToken`, `ProviderResolve`, `ErrorHandle`
+- **Chaining**: `ChatParams`, `ChatHeaders`, `PermissionAsk`, `ShellEnv`, `ToolExecuteBefore/After`, `SystemPromptTransform`, `ConfigTransform`, `SessionStart/End`, `MessageTransform`
+
+## Plugin Types
+
+| Type      | Mechanism                            | Status  |
+| --------- | ------------------------------------ | ------- |
+| `builtin` | Compiled in, registered via `init()` | ✅      |
+| `shared`  | `.so` loaded at runtime              | ✅      |
+| `exec`    | JSON-RPC over stdin/stdout           | 🚧 stub |
+
+## Conventions
+
+- **Files**: `<feature>.go` + `<feature>_test.go` (same package, white-box). Every package has a doc comment.
+- **Register**: `plugin.RegisterBuiltin("name", &Plugin{})` in `init()`. Tool names: `plugin_<plugin>_<tool>`.
+- **Hook I/O**: `<Hook>Input` (read-only) / `<Hook>Output` (mutable pointer); trigger `Trigger<Hook>`.
+- **Naming**: PascalCase exported; camelCase unexported consts (e.g., `credCacheTTL`).
+- **JSON tags**: all public types; `omitempty` optional; `json:"-"` for funcs.
+
+### Skeleton
+
+```go
+type Plugin struct { mu sync.RWMutex }
+func (p *Plugin) Meta() plugin.PluginMeta { ... }
+func (p *Plugin) Init(_ context.Context, in plugin.PluginInput) (*plugin.Hooks, error) {
+    return &plugin.Hooks{Tools: map[string]plugin.ToolDefinition{...}, Priority: 10}, nil
+}
+```
+
+### Rules
+
+- Wrap errors: `fmt.Errorf("desc: %w", err)`. Never ignore returned errors.
+- Tool errors → `ToolResponse{IsError: true}`, not Go errors. Hook errors → logged warnings; others still run.
+- Init map fields before writing (`if output.Env == nil { output.Env = make(...) }`).
+- Concurrency: `syncMap`, `eventBus`, `sync.RWMutex` on auth caches. Plugins init in parallel goroutines.
+
+### Testing
+
+- `t.Parallel()` unless mutating env / package-level state. Use `require` (not `assert`); plain-struct mocks.
+- Save/restore globals (`plugins`, `allTools`, `builtinPlugins`) via `defer`. Env tests: `t.Setenv()`, no `t.Parallel()`.
+
+## Standalone Constraint (Critical)
+
+`plugin/` (incl. `plugin/pkg/`) must have NO dependency on internal Codg packages (config, csync, pubsub, permission). External authors `go get github.com/vcaesar/codg/plugin` without the full tree. If internal types are needed, add standalone equivalents in `plugin/types.go`.
+
+## Known Issues
+
+Stubs: `plugin/auth/codex/codex.go`, `plugin/auth/gpt/`, `pkg/`. gopls: `unusedwrite` in tests (intentional); `stringsbuilder` at `oauthplugin/oauthplugin.go:156`.
+
+## Adding a Plugin / Hook
+
+- **Plugin**: `plugin/myplugin/` → implement `Init()` (+ optional `Meta()`); register in `init()`; tests + package doc. For `.so`: add `standalone/main.go` exporting `CodgPlugin`.
+- **Hook**: define `<Hook>Input/Output` in `plugin.go`; add to `Hooks` struct; add `Trigger<Hook>` (check `Handled` if short-circuiting); test in `plugin_test.go`; update `README.md` tables.