Adopt repo standards: scaffold, policies, lint-clean (closes #1)

Standard scaffold: script/ entrypoints with the Makefile as thin shims, a Dockerfile whose lint and test phases gate the build, a Gitea CI workflow running script/cibuild, REPO_POLICIES.md, TODO.md, .editorconfig, .dockerignore, LICENSE, wider .gitignore. .golangci.yml is byte-identical to the canonical copy in the prompts repo.

211 lint findings fixed in code: package globals became functions/fields and a cobra command constructor, magic numbers became named constants, ctx is threaded into the probes, monitor loops split. Tests moved to external _test packages with export_test.go. Behavior unchanged.

Readers will trip over: make lint/test/check now need a Docker daemon; the personal rsync copy/run targets are gone and make run runs locally.
Disclosure: four //nolint:gosec remain on the fixed-argv ping/curl calls and the operator-chosen log file, as the reference repo annotates the same class.
Disclosure: module path left as-is.

Model: opus-4-8 (implementation); fable-5-1 (merge)

internal/monitor/styles_test.go

@@ -1,104 +1,48 @@
 //go:build linux
-// +build linux
 
-package monitor
+package monitor_test
 
 import (
 	"testing"
 
 	tcell "github.com/gdamore/tcell/v2"
+
+	"git.eeqj.de/sneak/rtnetmon/internal/monitor"
 )
 
-// TestMeterColorForValue tests the MeterColorForValue function
 func TestMeterColorForValue(t *testing.T) {
-	tests := []struct {
-		name      string
-		value     int
-		maxValue  int
-		reverse   bool
-		wantColor tcell.Style
-	}{
-		// Reverse mode tests (low is good, high is bad)
-		{
-			name:      "reverse mode: 0% (best)",
-			value:     0,
-			maxValue:  10,
-			reverse:   true,
-			wantColor: CBrightGreen,
-		},
-		{
-			name:      "reverse mode: 10% (good)",
-			value:     1,
-			maxValue:  10,
-			reverse:   true,
-			wantColor: CBrightGreen,
-		},
-		{
-			name:      "reverse mode: 50% (medium)",
-			value:     5,
-			maxValue:  10,
-			reverse:   true,
-			wantColor: CYellow,
-		},
-		{
-			name:      "reverse mode: 90% (bad)",
-			value:     9,
-			maxValue:  10,
-			reverse:   true,
-			wantColor: CRed,
-		},
-		{
-			name:      "reverse mode: 100% (worst)",
-			value:     10,
-			maxValue:  10,
-			reverse:   true,
-			wantColor: CRed,
-		},
+	t.Parallel()
 
-		// Normal mode tests (high is good, low is bad)
-		{
-			name:      "normal mode: 0% (worst)",
-			value:     0,
-			maxValue:  10,
-			reverse:   false,
-			wantColor: CRed,
-		},
-		{
-			name:      "normal mode: 10% (bad)",
-			value:     1,
-			maxValue:  10,
-			reverse:   false,
-			wantColor: CRed,
-		},
-		{
-			name:      "normal mode: 50% (medium)",
-			value:     5,
-			maxValue:  10,
-			reverse:   false,
-			wantColor: CYellow,
-		},
-		{
-			name:      "normal mode: 90% (good)",
-			value:     9,
-			maxValue:  10,
-			reverse:   false,
-			wantColor: CBrightGreen,
-		},
-		{
-			name:      "normal mode: 100% (best)",
-			value:     10,
-			maxValue:  10,
-			reverse:   false,
-			wantColor: CBrightGreen,
-		},
+	green := tcell.StyleDefault.Foreground(tcell.ColorGreen).Bold(true)
+	yellow := tcell.StyleDefault.Foreground(tcell.ColorYellow)
+	red := tcell.StyleDefault.Foreground(tcell.ColorRed)
+
+	tests := []struct {
+		name            string
+		value, maxValue int
+		reverse         bool
+		want            tcell.Style
+	}{
+		{"reverse 0% best", 0, 10, true, green},
+		{"reverse 10% good", 1, 10, true, green},
+		{"reverse 50% medium", 5, 10, true, yellow},
+		{"reverse 90% bad", 9, 10, true, red},
+		{"reverse 100% worst", 10, 10, true, red},
+		{"normal 0% worst", 0, 10, false, red},
+		{"normal 10% bad", 1, 10, false, red},
+		{"normal 50% medium", 5, 10, false, yellow},
+		{"normal 90% good", 9, 10, false, green},
+		{"normal 100% best", 10, 10, false, green},
 	}
 
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
-			got := MeterColorForValue(tt.value, tt.maxValue, tt.reverse)
-			if got != tt.wantColor {
+			t.Parallel()
+
+			got := monitor.MeterColorForValue(tt.value, tt.maxValue, tt.reverse)
+			if got != tt.want {
 				t.Errorf("MeterColorForValue(%d, %d, %v) = %v, want %v",
-					tt.value, tt.maxValue, tt.reverse, got, tt.wantColor)
+					tt.value, tt.maxValue, tt.reverse, got, tt.want)
 			}
 		})
 	}