docs: update AGENTS.md and README with splash/config changes

AGENTS.md

@@ -52,26 +52,50 @@ V Panel is a Godot Engine project that builds a fancy real-time status monitor.
 - `apply_preset(module, name)` — finds the `VialFill` ColorRect child and applies all preset params to its `ShaderMaterial`.
 - `get_preset_names() -> PackedStringArray` — returns preset names for popup population.
 
+### Font Size Animation (Splash)
+- `Control.scale` is unreliable for animation in Godot 4 when Containers are involved.
+- `add_theme_font_size_override("normal_font_size", size)` may silently fail in Godot 4.6+ because `"normal_font_size"` is a deprecated alias. Use `label.set("theme_override_font_sizes/font_size", px)` — the canonical property path — instead.
+- `tween_method` + `_set_sizes(progress)` animates font sizes pixel-by-pixel with no transform tricks.
+
 ### Labels / Readability
 - All percentage labels get a 3px black outline (`outline_size` / `font_outline_color`) for legibility against the liquid shader background.
 - Title labels get a 2px outline.
 
+### Config System
+- `autoload/config_manager.gd` — autoload singleton using Godot's built-in `ConfigFile` class for INI-style config files.
+- Two files: `res://config/default.cfg` (shipped defaults, tracked) and `res://config/config.cfg` (user overrides, gitignored). User overrides are merged on top of defaults per-key.
+- Keys are flattened as `{section}_{key}` for simple `get_setting(key, default)` lookups (e.g., `[background]` + `color` => `"background_color"`).
+- `get_color(key, default_color)` parses `"r, g, b"` string values from config into `Color`.
+- `set_setting(key, value)` diffs against defaults and writes only the diff to `config.cfg` automatically.
+
+### Splash Screen
+- `scenes/splash.tscn` + `scenes/splash.gd` — entry point (set in `project.godot` as `main_scene`), handles fullscreen, font-size zoom animation, crossfade to dashboard.
+- Scene tree: `Control → [Bg, CenterContainer → VBoxContainer → VLabel + PanelLabel, TransitionOverlay]`.
+- Flow: Black overlay reveal (0.4s) → font-size animation with TRANS_BACK overshoot (2s) + parallel fade-in (1.8s) → hold (1s) → splash text fades out (1s, EASE_IN) → dashboard instantiated and fades in (1s, EASE_OUT) → reparent to root, queue_free splash.
+- Dashboard background (`PanelContainer`) and splash background (`ColorRect`) both read from `ConfigManager.get_color("background_color")` for a seamless crossfade — no fade-to-black transition.
+
 ### Project Structure
 ```
 res://
 ├── addons/          # Third-party plugins
 ├── assets/          # Fonts, icons, textures, audio
-│   ├── fonts/
+│   ├── fonts/       # Orbitron.ttf (variable weight)
 │   ├── icons/
-│   └── textures/   # noise_100.png (static noise for shader distortion)
+│   └── textures/    # noise_100.png (tileable Perlin noise for shader distortion)
 ├── autoload/        # Singleton/autoload scripts
+│   └── config_manager.gd   # INI config via ConfigFile
+├── config/          # Configuration files (INI format)
+│   ├── default.cfg  # Shipped defaults, tracked in git
+│   └── config.cfg   # User overrides, gitignored (auto-generated)
 ├── panels/          # Individual status panels (modules)
 │   ├── cpu/
 │   ├── memory/
 │   ├── network/
 │   ├── disk/
 │   └── testing/
-├── scenes/          # Root scenes (dashboard, etc.)
+├── scenes/          # Root scenes
+│   ├── splash.tscn  # Animated splash → dashboard transition
+│   └── dashboard.tscn  # Main dashboard (PanelContainer root)
 ├── scripts/         # Shared utility scripts
 │   ├── dashboard_grid.gd   # Responsive grid with drag, resize, preset popup
 │   ├── module_base.gd      # Base class for all modules (mouse_filter IGNORE)
@@ -80,7 +104,7 @@ res://
 ├── themes/          # Theme definitions and style resources
 ├── shaders/         # Custom shader materials
 │   └── vial_fill.gdshader  # Canvas-item shader with 3D water surface
-└── main.tscn        # Entry point (loads dashboard)
+└── main.tscn        # Legacy entry point (dashboard only)
 ```
 
 ### Key Implementation Details