fix(bridge): rawRPC direct polling + SDK analysis docs + trial-and-error log

- Root cause: getDiagnostics.lastStepIndex is stale, SDK EventMonitor cannot detect real-time step changes
- Fix: Direct rawRPC('GetCascadeTrajectorySteps') polling every 5s
- Relay: PLANNER_RESPONSE, NOTIFY_USER, TASK_BOUNDARY, WAITING steps
- Added: docs/discord-bridge-analysis.md (full SDK architecture analysis)
- Added: docs/devlog/entries/20260308-003.md (trial-and-error history)
- Added: antigravity-sdk-main/ source reference
- Vikunja: #252 done, #253 created, #251 commented

antigravity-sdk-main/tsconfig.json

@@ -0,0 +1,34 @@
+{
+    "compilerOptions": {
+        "target": "ES2020",
+        "module": "commonjs",
+        "lib": [
+            "ES2020"
+        ],
+        "outDir": "./dist",
+        "rootDir": "./src",
+        "strict": true,
+        "esModuleInterop": true,
+        "skipLibCheck": true,
+        "forceConsistentCasingInFileNames": true,
+        "declaration": true,
+        "declarationMap": true,
+        "sourceMap": true,
+        "resolveJsonModule": true,
+        "moduleResolution": "node",
+        "baseUrl": ".",
+        "paths": {
+            "@/*": [
+                "src/*"
+            ]
+        }
+    },
+    "include": [
+        "src/**/*"
+    ],
+    "exclude": [
+        "node_modules",
+        "dist",
+        "docs-site"
+    ]
+}