docs: benefit-focused crate-level rustdoc in Library.rs

Replace technical spec copy with developer-facing value propositions.
Remove 50-level analysis checklist where present.

Generated-By: PostHog Code
Task-Id: 556dae83-2866-4359-85ea-c7d0d818cb34

Author: NikolaRHristov

Source/Library.rs

@@ -1,17 +1,51 @@
 #![cfg_attr(not(debug_assertions), windows_subsystem = "windows")]
 #![allow(non_snake_case, non_camel_case_types, non_upper_case_globals)]
 
-//! # Common Crate
+//! # Common: Abstract Core Library for Code Editor Land
 //!
-//! Defines the abstract architectural core for the entire application
-//! ecosystem. It provides the foundational traits, services, and data transfer
-//! objects (DTOs) that constitute the application's public API contract.
+//! Every Element in Land depends on Common. It defines the traits, services,
+//! and data transfer objects that form the application's public API contract.
+//! Mountain implements these traits. Wind and Cocoon consume them.
 //!
-//! This crate enforces a clean separation of concerns by defining "what" an
-//! operation does (the service trait, e.g., `FileSystemReader`) separately
-//! from "how" it is implemented (the concrete implementation in the `Mountain`
-//! crate). This declarative, effects-based architecture ensures that
-//! application logic is composable, testable, and maintainable.
+//! ## Why Common Exists
+//!
+//! Common enforces a clean separation between "what the app can do" (traits)
+//! and "how it does it" (Mountain's concrete implementations). This means:
+//!
+//! - You can test business logic without launching Tauri
+//! - New backends can implement the same traits
+//! - The TypeScript frontend only needs to know the DTO shapes
+//!
+//! ## Key Abstractions
+//!
+//! - **ActionEffect**: Declarative effect type executed by Mountain's runtime.
+//!   Business logic is described as composable effects, not imperative calls.
+//! - **Service traits**: FileSystemService, ProcessService, ExtensionService,
+//!   and 15 more domain-specific contracts.
+//! - **DTOs**: Type-safe data objects shared across IPC boundaries (gRPC,
+//!   Tauri commands, WebSocket).
+//! - **Error types**: Structured errors with context for every service domain.
+//!
+//! ## Module Layout
+//!
+//! | Module | Contents |
+//! |---|---|
+//! | `Effect/` | ActionEffect enum, builders, and combinators |
+//! | `Environment/` | Capability provider trait (dependency injection) |
+//! | `Error/` | Domain-specific error types with context |
+//! | `Transport/` | Transport-agnostic communication (gRPC, IPC, WASM) |
+//! | `DTO/` | Re-exported data transfer objects from all services |
+//! | `Command/` .. `Workspace/` | Service trait definitions (20 domains) |
+//!
+//! ## Getting Started
+//!
+//! Common builds as part of the Land monorepo:
+//! ```bash
+//! cargo build -p Common
+//! cargo test -p Common
+//! ```
+//!
+//! Full setup: <https://github.com/CodeEditorLand/Land>
 
 // --- Core Architecture ---
 pub mod Effect;