Rewrite Strix from scratch as single binary

Complete architecture rewrite following go2rtc patterns:
- pkg/ for pure logic (camdb, tester, probe, generate)
- internal/ for application glue with Init() modules
- Single HTTP server on :4567 with all endpoints
- zerolog with password masking and memory ring buffer
- Environment-based config only (no YAML files)

API endpoints: /api/search, /api/streams, /api/test,
/api/probe, /api/generate, /api/health, /api/log

Dependencies: go2rtc v1.9.14, go-sqlite3, miekg/dns, zerolog

pkg/generate/diff.go

@@ -0,0 +1,36 @@
+package generate
+
+import "strings"
+
+func fullDiff(config string) []DiffLine {
+	lines := strings.Split(config, "\n")
+	diff := make([]DiffLine, len(lines))
+	for i, line := range lines {
+		diff[i] = DiffLine{Line: i + 1, Text: line, Type: "added"}
+	}
+	return diff
+}
+
+func diffWithContext(lines []string, added map[int]bool, ctx int) []DiffLine {
+	visible := make(map[int]bool)
+	for idx := range added {
+		for c := -ctx; c <= ctx; c++ {
+			if j := idx + c; j >= 0 && j < len(lines) {
+				visible[j] = true
+			}
+		}
+	}
+
+	var diff []DiffLine
+	for i, line := range lines {
+		if !visible[i] {
+			continue
+		}
+		t := "context"
+		if added[i] {
+			t = "added"
+		}
+		diff = append(diff, DiffLine{Line: i + 1, Text: line, Type: t})
+	}
+	return diff
+}