feat(typescript): implement type-safe database error handling and eliminate any types

- Add comprehensive database error interfaces (DatabaseConstraintError, DatabaseStorageError, DexieError)
- Implement type guards for database error handling (isDatabaseError, isDatabaseConstraintError, etc.)
- Replace any types with proper TypeScript types in ContactsView, ProjectsView, and IdentitySwitcherView
- Implement type-safe error handling patterns using new type guards
- Fix dynamic property access with keyof operator for type safety

Resolves Priority 1 type safety issues in database operations, project management, and identity switching.

src/interfaces/common.ts

@@ -98,3 +98,81 @@ export interface VerifiableCredentialClaim {
   credentialSubject: ClaimObject;
   [key: string]: unknown;
 }
+
+/**
+ * Database constraint error types for consistent error handling
+ */
+export interface DatabaseConstraintError extends Error {
+  name: "ConstraintError";
+  message: string;
+  constraint?: string;
+}
+
+/**
+ * Database storage error types for IndexedDB/SQLite operations
+ */
+export interface DatabaseStorageError extends Error {
+  name: "StorageError";
+  message: string;
+  code?: string;
+  constraint?: string;
+}
+
+/**
+ * Legacy Dexie error types for migration compatibility
+ */
+export interface DexieError extends Error {
+  name: string;
+  message: string;
+  inner?: unknown;
+  stack?: string;
+}
+
+/**
+ * Type guard for database constraint errors
+ */
+export function isDatabaseConstraintError(
+  error: unknown,
+): error is DatabaseConstraintError {
+  return error instanceof Error && error.name === "ConstraintError";
+}
+
+/**
+ * Type guard for database storage errors
+ */
+export function isDatabaseStorageError(
+  error: unknown,
+): error is DatabaseStorageError {
+  return error instanceof Error && error.name === "StorageError";
+}
+
+/**
+ * Type guard for legacy Dexie errors
+ */
+export function isDexieError(error: unknown): error is DexieError {
+  return (
+    error instanceof Error &&
+    (error.name === "DexieError" ||
+      error.message.includes("Key already exists in the object store") ||
+      error.message.includes("ConstraintError"))
+  );
+}
+
+/**
+ * Unified error type for database operations
+ */
+export type DatabaseError =
+  | DatabaseConstraintError
+  | DatabaseStorageError
+  | DexieError;
+
+/**
+ * Type guard for any database error
+ */
+export function isDatabaseError(error: unknown): error is DatabaseError {
+  return (
+    isDatabaseConstraintError(error) ||
+    isDatabaseStorageError(error) ||
+    isDexieError(error)
+  );
+}