feat(plugins): Implement complete WASM-based plugin system (#495)

* feat(plugins): Implement complete WASM-based plugin system

This PR implements a comprehensive plugin system for Cortex CLI that allows
users to create custom plugins in WebAssembly (WASM) using Rust.

## Features

### Plugin Architecture
- WASM runtime using wasmtime v29 for sandboxed plugin execution
- Plugin manifest system (plugin.toml) with capabilities, permissions, commands, and hooks
- Complete plugin lifecycle management (discover, load, init, shutdown, unload)

### Plugin API
- File system access (read/write with permission controls)
- Shell command execution (with allowed commands list)
- HTTP requests (with domain restrictions)
- Configuration and storage APIs
- Logging and notifications

### Hook System
- tool.execute.before: Intercept and modify tool arguments
- tool.execute.after: Post-process tool results
- chat.message: Process chat messages
- permission.ask: Override permission decisions

### Event System
- Session events (start/end)
- Tool execution events
- Plugin lifecycle events
- Custom plugin events

### TUI Integration
- Enhanced /plugins command with subcommands:
  - /plugins list - List installed plugins
  - /plugins info <id> - Show plugin details
  - /plugins enable/disable <id> - Toggle plugins
  - /plugins install/uninstall - Manage plugins
  - /plugins create <name> - Scaffold new plugin

### Plugin SDK
- Template for plugin manifest (plugin.toml)
- Rust code template for WASM plugins
- Cargo.toml template with wasm32-wasi target
- PluginDev::scaffold() for generating plugin projects

## Files Changed

### New Files (cortex-plugins/src/)
- error.rs: Plugin error types
- manifest.rs: TOML manifest parsing and validation
- config.rs: Plugin configuration
- plugin.rs: Plugin trait and types
- events.rs: Event bus system
- hooks.rs: Hook registry and dispatcher
- commands.rs: Plugin command registry
- api.rs: Plugin host functions
- runtime.rs: WASM runtime with wasmtime
- loader.rs: Plugin discovery and loading
- registry.rs: Plugin registry
- manager.rs: Main plugin manager
- sdk.rs: Plugin development SDK

### Modified Files
- cortex-plugins/Cargo.toml: Added wasmtime, tokio, reqwest dependencies
- cortex-plugins/src/lib.rs: Re-exports and module structure
- cortex-tui/src/commands/registry.rs: Enhanced /plugins command
- cortex-tui/src/commands/executor.rs: Plugin command handlers

## Testing
- All 41 cortex-plugins tests pass
- All 159 cortex-tui command tests pass
- cargo clippy passes with no warnings

* feat(plugins): Add comprehensive VSCode-like hook system with 24+ hook types

This commit dramatically enhances the plugin system to be comparable to VSCode plugins
with comprehensive event hooks and interception capabilities.

New Hook Types Added:
- Prompt Injection: PromptInjectHook for AI prompt modification
- AI Response: AiResponseBeforeHook, AiResponseStreamHook, AiResponseAfterHook
- File Operations: FileOperationBeforeHook/AfterHook with deny capability
- Command Execution: CommandExecuteBeforeHook/AfterHook with output replacement
- Input Interception: InputInterceptHook with autocomplete and text expansion
- Error Handling: ErrorHandleHook with recovery actions
- Config Changes: ConfigChangedHook with pattern matching
- Session Lifecycle: SessionStartHook, SessionEndHook with context injection
- Workspace: WorkspaceChangedHook with project type detection
- Clipboard: ClipboardCopyHook, ClipboardPasteHook
- UI Rendering: UiRenderHook for custom widgets
- Focus Changes: FocusChangeHook for app focus events

Event System Expansion (13 → 40+ events):
- Session: SessionResumed
- Tool: ToolExecutionAborted
- AI: AiResponseStarted, AiResponseChunk, AiResponseCompleted, AiResponseError
- File: FileCreated, FileDeleted, FileRenamed
- Command: CommandStarted, CommandCompleted
- Config: AgentChanged
- Workspace: WorkspaceChanged, ProjectDetected
- Plugin: PluginInitialized, PluginDisabled, PluginEnabled, PluginMessage
- Error: ErrorOccurred
- Clipboard: ClipboardCopy, ClipboardPaste
- Focus: FocusGained, FocusLost
- Permission: PermissionRequested, PermissionGranted, PermissionDenied

Key Features:
- All hooks support priority ordering for execution order control
- Pattern matching for targeted hook triggers
- Flow control: Continue/Skip/Abort/Replace for all hooks
- Inter-plugin communication via PluginMessage event
- Complete Input/Output type system with proper serialization
- Full backward compatibility with existing plugin code

---------

Co-authored-by: Droid Agent <droid@factory.ai>

Author: echobt

Cargo.lock

@@ -1,14 +1,57 @@
 [package]
 name = "cortex-plugins"
-version = "0.1.0"
-edition = "2021"
-description = "Plugin system for Cortex CLI"
+version.workspace = true
+edition.workspace = true
+rust-version.workspace = true
+authors.workspace = true
+license.workspace = true
+repository.workspace = true
+description = "Complete WASM-based plugin system for Cortex CLI"
 
 [dependencies]
-tokio = { version = "1", features = ["full"] }
-serde = { version = "1", features = ["derive"] }
-serde_json = "1"
-tracing = "0.1"
-thiserror = "1"
-async-trait = "0.1"
-dirs = "5"
+# Async runtime
+tokio = { workspace = true }
+
+# Serialization
+serde = { workspace = true }
+serde_json = { workspace = true }
+toml = { workspace = true }
+
+# Error handling
+thiserror = { workspace = true }
+anyhow = { workspace = true }
+
+# Logging
+tracing = { workspace = true }
+
+# Async traits
+async-trait = { workspace = true }
+
+# Utilities
+dirs = { workspace = true }
+uuid = { workspace = true }
+chrono = { workspace = true }
+semver = "1.0"
+sha2 = { workspace = true }
+hex = { workspace = true }
+
+# WASM Runtime
+wasmtime = { version = "29", features = ["async", "component-model"] }
+wasmtime-wasi = { version = "29" }
+
+# HTTP client for plugin network access
+reqwest = { workspace = true }
+
+# URL parsing
+url = { workspace = true }
+
+# File watching for hot-reload
+notify = { workspace = true }
+
+# Concurrent data structures
+dashmap = { workspace = true }
+parking_lot = { workspace = true }
+
+[dev-dependencies]
+tempfile = { workspace = true }
+tokio-test = { workspace = true }