fix(client): align api_create_user IPC argument casing between frontend and tauri backend

client-tauri/src/Settings.tsx

@@ -201,6 +201,8 @@ export default function Settings({ email, onLogout }: SettingsProps) {
     try {
       await invoke("api_create_user", {
         email: newUserEmail,
+        firstName: newUserFirst,
+        lastName: newUserLast,
         first_name: newUserFirst,
         last_name: newUserLast,
       });

openspec/changes/fix-client-create-user-ipc-arguments/.openspec.yaml

@@ -0,0 +1,2 @@
+schema: spec-driven
+created: 2026-11-04

openspec/changes/fix-client-create-user-ipc-arguments/design.md

@@ -0,0 +1,31 @@
+## Context
+
+See `proposal.md` for background and problem statement. In `client-tauri/src/Settings.tsx`, `handleCreateUser` calls `invoke("api_create_user", { email: newUserEmail, first_name: newUserFirst, last_name: newUserLast })`.
+In `client-tauri/src-tauri/src/lib.rs`, `api_create_user` is defined as:
+```rust
+#[tauri::command]
+fn api_create_user(email: String, first_name: String, last_name: String) -> Result<serde_json::Value, String>
+```
+Tauri's procedural macro converts Rust parameter names to `lowerCamelCase` when deserializing incoming JSON arguments unless explicitly configured with `rename_all`. As a result, Tauri expects `firstName` and `lastName`. Because `Settings.tsx` supplies `first_name` and `last_name`, Tauri IPC throws a deserialization error (`missing required key firstName`) and aborts the command before invoking the backend API.
+
+## Goals / Non-Goals
+
+**Goals:**
+- Fix `handleCreateUser` in `Settings.tsx` to supply `firstName` and `lastName` to satisfy Tauri's IPC deserializer.
+- Provide both `firstName`/`lastName` and `first_name`/`last_name` in the invocation payload to maintain full forward/backward compatibility.
+- Ensure the desktop client build and static analysis succeed without regressions.
+
+**Non-Goals:**
+- Changing backend FastAPI HTTP endpoints (FastAPI expects snake_case, which `api.rs` already formats in `CreateUserBody`).
+- Altering the user creation modal UX or password handling.
+
+## Decisions
+
+### Decision 1: Frontend Payload Parameter Casing Alignment
+- **Choice**: In `Settings.tsx`, pass `firstName: newUserFirst, lastName: newUserLast, first_name: newUserFirst, last_name: newUserLast`.
+- **Rationale**: Tauri v2 `CommandItem::deserialize_json` expects `firstName` and `lastName` based on Rust parameter names. Passing both camelCase and snake_case ensures that default Tauri command deserialization succeeds immediately while safeguarding against any variant expectations.
+- **Alternatives considered**: Adding `#[tauri::command(rename_all = "snake_case")]` in `lib.rs`. While valid, all other commands across the Tauri client (`api_change_password`, `set_sync_folder_path`, etc.) follow the standard Tauri camelCase convention. Aligning the frontend invocation maintains consistency across the entire client IPC layer.
+
+## Risks / Trade-offs
+
+- None identified. Passing additional keys in the JSON payload is safely ignored by Tauri's IPC deserializer.

openspec/changes/fix-client-create-user-ipc-arguments/proposal.md

@@ -0,0 +1,27 @@
+## Why
+
+In the Tauri desktop client (`client-tauri`), the user administration dialog allows administrators to create new users. When submitting the user creation form, `Settings.tsx` invokes the Tauri command `api_create_user` with a payload containing `{ email, first_name, last_name }`.
+
+However, Tauri's `#[tauri::command]` procedural macro converts Rust parameter names (`email`, `first_name`, `last_name`) to `lowerCamelCase` (`email`, `firstName`, `lastName`) for IPC command arguments by default. Tauri's JSON deserializer strictly expects the keys `"firstName"` and `"lastName"`. Because the frontend sends snake_case keys (`first_name`, `last_name`), Tauri fails deserialization immediately with:
+`command api_create_user missing required key firstName`.
+
+As a result, creating a new user from the desktop client settings UI always fails with an error and cannot be completed.
+
+## What Changes
+
+- Update `handleCreateUser` in `client-tauri/src/Settings.tsx` to supply camelCase parameter keys (`firstName`, `lastName`) as required by Tauri's IPC deserializer, while also providing `first_name` and `last_name` for defense-in-depth compatibility.
+- Ensure the user creation flow correctly completes against the Tauri IPC command interface.
+
+## Capabilities
+
+### New Capabilities
+<!-- None -->
+
+### Modified Capabilities
+- `desktop-client`: Align Tauri IPC command invocation parameters for `api_create_user` with Tauri's command deserialization requirements (`firstName` and `lastName`).
+
+## Impact
+
+- Affected files: `client-tauri/src/Settings.tsx`.
+- User-facing impact: Administrators can successfully create new user accounts from the desktop client settings interface without encountering `missing required key firstName` errors.
+- No breaking changes or external dependencies added.

openspec/changes/fix-client-create-user-ipc-arguments/specs/desktop-client/spec.md

@@ -0,0 +1,9 @@
+## ADDED Requirements
+
+### Requirement: Desktop Client User Creation IPC Compatibility
+The desktop client settings UI SHALL supply user creation arguments adhering to Tauri's lowerCamelCase IPC parameter conventions (`firstName` and `lastName`) when invoking the `api_create_user` command.
+
+#### Scenario: Submitting new user form from settings
+- **WHEN** an administrator enters email, first name, and last name and submits the user creation dialog
+- **THEN** the frontend invokes `api_create_user` with `firstName` and `lastName` matching the deserialization contract of the Tauri command handler
+- **AND** the command does not fail with `missing required key firstName` or parameter deserialization errors

openspec/changes/fix-client-create-user-ipc-arguments/tasks.md

@@ -0,0 +1,9 @@
+## 1. Implementation
+
+- [x] 1.1 Update `handleCreateUser` in `client-tauri/src/Settings.tsx` to include `firstName` and `lastName` (along with `first_name` and `last_name`) in the `api_create_user` invocation payload
+
+## 2. Verification
+
+- [x] 2.1 Build `client-tauri` frontend (`npm run build`) and verify TypeScript compilation and bundle generation succeed
+- [x] 2.2 Run `cargo test` in `client-tauri/src-tauri` and verify all desktop client tests pass
+- [x] 2.3 Run `./scripts/run-qa.sh` or relevant verification checks to ensure no regressions