test: add 34 tests for GraphResilienceAnalyzer

fix: correct self-referencing LOGGER initialization in Main.java

GraphResilienceAnalyzer had zero test coverage despite implementing
three attack simulation strategies for network resilience analysis.

Tests cover:

Pre-analysis guards:
- getDegreeAttackCurve/getBetweennessAttackCurve/getRandomAttackCurve
  all throw IllegalStateException before analyze() is called
- getSummary/exportCSV throw before analyze()

Degree-based attack:
- First step captures full graph state (LCC=N, components=1)
- Curve length is N+1 (initial + N removals)
- Last step has 0 nodes remaining
- Star graph: center (highest degree) removed first, all leaves
  become isolated (LCC=1, 5 components)

Betweenness-based attack:
- Path graph: v2 (highest betweenness) removed first
- LCC monotonically decreases across curve

Random attack:
- Curve length is N+1
- First step has full graph, last step has 0 LCC
- Custom trial count works correctly
- setRandomTrials(0) clamped to 1

Robustness index:
- Always in [0, 1] range
- Null/empty curve returns 0
- Complete graph more resilient than star (degree attack)
- Star: random attack shows higher resilience than degree attack

Global efficiency:
- Triangle has efficiency 1.0 (all pairs distance 1)
- Efficiency decreases after node removal

Edge cases:
- Single node graph: 2-step curve
- Two-node graph: 3-step curve with correct LCC progression
- Disconnected graph (two triangles): correct LCC=3, components=2

Summary/Export:
- Contains expected sections and formatting
- CSV has correct header and line count

Also fixes Main.java line 54: LOGGER was self-referencing
(private static final Logger LOGGER = LOGGER) instead of calling
Logger.getLogger(Main.class.getName()) — this was introduced
during the logger consolidation in commit bfb05d4.

Author: sauravbhattacharya001

Gvisual/src/gvisual/Main.java

@@ -51,7 +51,7 @@
  */
 public class Main extends JFrame {
 
-    private static final Logger LOGGER = LOGGER;
+    private static final Logger LOGGER = Logger.getLogger(Main.class.getName());
     private static final Color DEFAULT_BG_COLOR = Color.BLACK;
     private static final Color Vertex_COLOR = Color.WHITE;
     private static int DELAY = 2048;