docs: improve README branding and update config to PERFDECK_CONFIG

Author: sumant1122

README.md

@@ -1,6 +1,6 @@
 <div align="center">
 
-# 📊 perfdeck
+# 📊 Perfdeck
 
 **A modern, lightweight, and customizable TUI performance monitor for your terminal.**
 
@@ -16,9 +16,9 @@
 
 ---
 
-## 💡 Why perfdeck?
+## 💡 Why Perfdeck?
 
-Traditional performance monitors often overwhelm users with information or lack the flexibility to show exactly what you need. **perfdeck** solves this by providing:
+Traditional performance monitors often overwhelm users with information or lack the flexibility to show exactly what you need. **Perfdeck** solves this by providing:
 
 -   **Consolidation**: View output from multiple diagnostic tools (like `top`, `vmstat`, `netstat`) in one place.
 -   **Focus**: A clean, tabbed interface lets you switch between different metrics without terminal clutter.
@@ -37,10 +37,10 @@ Traditional performance monitors often overwhelm users with information or lack
 ## 📸 Screenshots
 
 ### Dark Mode (Default)
-![perfdeck Dark Mode](https://github.com/user-attachments/assets/7a94f63d-02ee-4992-b66d-9adf42a16603)
+![Perfdeck Dark Mode](https://github.com/user-attachments/assets/7a94f63d-02ee-4992-b66d-9adf42a16603)
 
 ### Light Mode
-![perfdeck Light Mode](https://github.com/user-attachments/assets/19025abf-63e0-49c3-b5a5-c5c07f62468b)
+![Perfdeck Light Mode](https://github.com/user-attachments/assets/19025abf-63e0-49c3-b5a5-c5c07f62468b)
 
 ## 🚀 Installation
 
@@ -74,12 +74,12 @@ perfdeck
 | `j` / `k` (or `↓`/`↑`) | Scroll through command output |
 | `t` | Toggle Light/Dark theme |
 | `v` | Display version information |
-| `q` / `Esc` / `Ctrl+C` | Exit perfdeck |
+| `q` / `Esc` / `Ctrl+C` | Exit Perfdeck |
 
 ## ⚙️ Configuration
 
-perfdeck is designed to be personalized. It looks for `perfdeck.toml` in:
-1.  `$PERFMON_CONFIG`
+Perfdeck is designed to be personalized. It looks for `perfdeck.toml` in:
+1.  `$PERFDECK_CONFIG`
 2.  `~/.config/perfdeck/config.toml`
 3.  Current working directory
 

internal/config/config.go

@@ -92,13 +92,13 @@ func loadFromConfig() (Config, bool) {
 
 func configPaths() []string {
 	var paths []string
-	if env := strings.TrimSpace(os.Getenv("PERFMON_CONFIG")); env != "" {
+	if env := strings.TrimSpace(os.Getenv("PERFDECK_CONFIG")); env != "" {
 		paths = append(paths, env)
 	}
 	if cfgDir, err := os.UserConfigDir(); err == nil {
-		paths = append(paths, filepath.Join(cfgDir, "perfmon", "config.toml"))
+		paths = append(paths, filepath.Join(cfgDir, "perfdeck", "config.toml"))
 	}
-	paths = append(paths, "perfmon.toml")
+	paths = append(paths, "perfdeck.toml")
 	return paths
 }
 

internal/config/config_test.go

@@ -43,7 +43,7 @@ refresh_interval = "1s"
 
 func TestLoadTabsFromConfig(t *testing.T) {
 	dir := t.TempDir()
-	path := filepath.Join(dir, "perfmon.toml")
+	path := filepath.Join(dir, "perfdeck.toml")
 	err := os.WriteFile(path, []byte(`
 global_refresh_interval = "2s"
 [[tab]]
@@ -54,7 +54,7 @@ cmd = ["vmstat"]
 		t.Fatalf("write: %v", err)
 	}
 
-	t.Setenv("PERFMON_CONFIG", path)
+	t.Setenv("PERFDECK_CONFIG", path)
 	_, tabs := Load() // Load now returns (Config, []Tab)
 
 	if len(tabs) != 1 {