docs: refresh README to reflect current addon state (#42)

README.md

@@ -11,16 +11,21 @@
 
 </div>
 
+PhDamage is a high-precision expected damage and healing calculator built specifically for the TBC Anniversary
+environment. It dynamically computes spell values by processing the full TBC combat formula - including base values,
+spell power coefficients, talent multipliers, and aura modifiers - and projects these results directly onto action
+bar buttons and tooltips for real-time performance feedback.
+
 ## 🎯 Features
 
-- Real-time expected damage and healing on spell tooltips, accounting for hit chance, crit chance, and talent modifiers
-- Action bar overlays showing expected damage directly on your buttons
-- School-colored companion tooltip with spell name, rank, and full stat breakdown
-- All 9 classes supported: Druid, Hunter, Mage, Paladin, Priest, Rogue, Shaman, Warlock, Warrior
-- All spell types: direct, DoT, channel, hybrid, melee, ranged, and utility
-- Automatically updates when your talents, gear, buffs, or debuffs change
-- ElvUI skin matching when detected
-- Lightweight with no runtime overhead - calculations only trigger on state changes
+- **Real-Time Computation**: Full TBC formula processing (base + coefficient × spell power, talents, auras) for
+  expected damage and healing values.
+- **Action Bar Overlay**: Direct visualization of computed values on every action bar button.
+- **Configurable UI**: Adjustable overlay placement (anchor, offset), font size, and number abbreviation (k/M suffixes).
+- **Deep Tooltip Integration**: Detailed spell breakdown including rank-specific info and modifier impacts.
+- **Diagnostic Inspection**: Slash commands to inspect crit chance, modifier stacks, and the current player state.
+- **Zero Overhead**: High-performance architecture with cached calculations that only recompute on state changes.
+- **Class Support**: Comprehensive data for all 9 classes and all spell types (Direct, DoT, Channel, Hybrid).
 
 ## 🎮 Supported Versions
 
@@ -38,29 +43,62 @@
 
 ### Manual Install
 
-1. Download the latest release from one of the sources above
+1. Download the latest release from one of the sources above.
 2. Extract the `PhDamage` folder into your AddOns directory:
 
    ```text
    World of Warcraft/_anniversary_/Interface/AddOns/PhDamage/
    ```
 
-3. Restart WoW or type `/reload`
+3. Restart WoW or type `/reload`.
+
+## ⚙️ Configuration
+
+Use `/phd config` to open the options panel (also available via Blizzard Interface > AddOns > PhDamage). All settings
+are backed by AceDB profiles and apply immediately without requiring a UI reload.
+
+| Setting            | Range / Values                                                              |
+|:-------------------|:----------------------------------------------------------------------------|
+| Anchor             | TOPLEFT, TOP, TOPRIGHT, LEFT, CENTER, RIGHT, BOTTOMLEFT, BOTTOM, BOTTOMRIGHT |
+| Horizontal Offset  | -50 to 50 px (step 1)                                                       |
+| Vertical Offset    | -50 to 50 px (step 1)                                                       |
+| Font Size          | 6 to 32 (step 1)                                                            |
+| Abbreviate Numbers | Toggle (shortens 1500 to 1.5k)                                              |
+| Reset to Defaults  | Button to restore original settings                                         |
 
 ## ⌨️ Commands
 
 All commands use the `/phd` prefix (or the full `/phdamage`):
 
-| Command            | Description                              |
-|:-------------------|:-----------------------------------------|
-| `/phd`             | Show diagnostic information for all spells |
-| `/phd state`       | Show current player state snapshot       |
-| `/phd spell <name>` | Detailed breakdown for a specific spell |
-| `/phd help`        | List available commands                  |
+| Command               | Description                                           |
+|:----------------------|:------------------------------------------------------|
+| `/phd`                | Prints expected damage/healing for all known spells   |
+| `/phd state`          | Prints current player state snapshot (stats, auras)   |
+| `/phd spell <target>` | Prints computation for one spell (name, spellID, link)|
+| `/phd config`         | Opens the options panel                               |
+| `/phd help`           | Prints the command list                               |
+
+## 🏗 Architecture
+
+The addon enforces a strict 4-layer separation to ensure the core engine remains pure and testable outside of the
+World of Warcraft environment.
+
+| Layer        | Directory        | Responsibility                                                               |
+|:-------------|:-----------------|:-----------------------------------------------------------------------------|
+| Shell        | `Core/`          | Owns lifecycle, slash commands, and options; the only layer calling WoW APIs |
+| Engine       | `Engine/`        | Pure Lua computation pipeline (coefficients, talents, crit); zero WoW deps  |
+| Data         | `Data/`          | Declarative tables for spell data, talent maps, and aura modifiers           |
+| Presentation | `Presentation/`  | Display logic including action bar overlays and tooltip formatting           |
+
+## 🧪 Development
+
+Contributors should refer to `AGENTS.md` for full coding standards. The project maintains a 36-spec test suite powered
+by busted. Run `luacheck .` for linting and `busted --verbose` to verify the engine before submitting pull requests.
 
 ## 🤝 Contributing
 
-Contributions are welcome! Please read [CONTRIBUTING.md](CONTRIBUTING.md) for setup, coding standards, and the PR process. All contributors are expected to follow the [Code of Conduct](CODE_OF_CONDUCT.md).
+Contributions are welcome! Please read [CONTRIBUTING.md](CONTRIBUTING.md) for setup, coding standards, and the PR
+process. All contributors are expected to follow the [Code of Conduct](CODE_OF_CONDUCT.md).
 
 ## ❤️ Support