feat: add tsconfig with strict flags for additional safety

tsconfig.json

@@ -0,0 +1,47 @@
+{
+  "compilerOptions": {
+    // Base strict mode
+    "strict": true,
+
+    // === THE FIVE EXTRA FLAGS ===
+
+    // 1. Array/object indexing returns T | undefined (not just T)
+    "noUncheckedIndexedAccess": true,
+
+    // 2. Optional properties (?) mean "absent", not "undefined"
+    "exactOptionalPropertyTypes": true,
+
+    // 3. Forces obj["key"] syntax for index signatures (explicit about dynamic access)
+    "noPropertyAccessFromIndexSignature": true,
+
+    // 4. Error on unused local variables
+    "noUnusedLocals": true,
+
+    // 5. Error on unused function parameters
+    "noUnusedParameters": true,
+
+    // === ADDITIONAL SAFETY ===
+
+    // Error if switch case falls through without break
+    "noFallthroughCasesInSwitch": true,
+
+    // Error if function doesn't explicitly return in all paths
+    "noImplicitReturns": true,
+
+    // Force consistent casing in imports (catches cross-platform bugs)
+    "forceConsistentCasingInFileNames": true,
+
+    // Ensure imports resolve correctly
+    "moduleResolution": "bundler",
+    "module": "ESNext",
+    "target": "ES2022",
+    "lib": ["ES2023", "DOM", "DOM.Iterable"],
+
+    // Isolated builds (required for most bundlers)
+    "isolatedModules": true,
+    "verbatimModuleSyntax": true,
+
+    // Skip type-checking node_modules
+    "skipLibCheck": true,
+  },
+}