feat: Add harbor project update command

## Problem

`harbor project` has `create`, `delete`, `list`, and `view`, but no `update`. The Harbor WebUI lets you change project settings after creation. The CLI does not expose that in one place.

Today you have to use separate commands:

- `harbor project config update` for metadata (public, auto-scan, prevent-vul, severity, reuse system CVE allowlist)
- `harbor quota update` for storage quota

Proxy cache registry ID can only be set at create time via `harbor project create --registry-id`. There is no top-level project update command matching the rest of the project CRUD surface.

## Proposed Solution

Add `harbor project update [name]` with flags and an interactive form.

**Command**

```sh
harbor project update [project_name] [flags]
```

**Flags**

- `--public` (true/false)
- `--auto-scan` (true/false)
- `--prevent-vul` (true/false)
- `--reuse-sys-cve` (true/false)
- `--severity` (none, low, medium, high, critical)
- `--storage-limit` (bytes, -1 for unlimited)
- `--registry-id` (proxy cache projects)
- `--id` (use project ID instead of name)

**Behavior**

1. Resolve project by name or ID, or prompt if omitted.
2. Fetch current project state.
3. If flags are passed, apply those fields. Otherwise run an interactive form.
4. Call `UpdateProject` in `pkg/api/project_handler.go` with `Public`, `Metadata`, and `RegistryID` where relevant.
5. Update storage quota via the quota API when storage changes.

**Files**

- `cmd/harbor/root/project/update.go`
- `pkg/api/project_handler.go` (`UpdateProject`)
- `pkg/views/project/update/view.go`
- `cmd/harbor/root/project/update_test.go`
- Regenerated docs under `doc/cli-docs/` and `doc/man-docs/`

**Examples**

```sh
harbor project update myproject --public true
harbor project update myproject --storage-limit -1 --prevent-vul true
harbor project update myproject
```

## Alternatives Considered

**Extend `harbor project config update` only**

This command already updates metadata via `api.UpdateConfig`. It does not cover storage quota or registry ID, and it lives under `project config` instead of alongside create/delete/list/view.

**Keep using `harbor quota update` for storage**

Works today but splits project management across two commands. Users expect `harbor project update` for WebUI parity.

**Do nothing**

Users keep juggling `project config update` and `quota update`. No single command for scripts or interactive project edits.

## Additional Context

- WebUI parity is the main driver. Project settings are editable in the UI after creation.
- `pkg/api/project_config_handler.go` already calls Harbor `UpdateProject` but only sends `Metadata`. A dedicated `UpdateProject` in `project_handler.go` can send the full `ProjectReq` (`Public`, `Metadata`, `RegistryID`).
- Implementation should follow existing patterns in `project/create.go`, `repository/update.go`, and `project/config/update.go`.
- A draft implementation exists on branch `feat/project-update` in fork `false200/harbor-cli`.
- Tests added so far cover flag validation only. Live Harbor integration testing is still needed before merge.

Start by comparing cmd/harbor/root/project/create.go, repository/update.go, project/config/update.go, and the listed view and test files. Review pkg/api/project_handler.go and project_config_handler.go, then verify flag validation and live Harbor behavior; done means the command supports the specified project fields, quota updates, interactive use, tests, and regenerated docs.

Written by the indexing model from the issue text.