refactor: move buildable .NET source into src/, update CI/doc paths

Groups the repo root into src (buildable source), docs (already existed),
and everything else (db/, scripts/, tests/, deploy/ - deployment/ops/test
assets that aren't compiled, already organized as their own folders). CI
now only needs src/ to build: dotnet restore/build/test/publish all point
at src/TaxBaik.sln, src/TaxBaik.Web/, src/TaxBaik.Proxy/.

- git mv every project (Domain, Infrastructure, Application,
  Application.Tests, Web, Web.Client, Proxy) and TaxBaik.sln into src/ as a
  unit, so relative ProjectReference/.sln paths stay valid unchanged.
- .gitea/workflows/deploy.yml: 6 dotnet restore/clean/build/test/publish
  invocations now point at src/. db/migrations and scripts/ stay at root
  (deploy_gb.sh and browser-e2e.yml only touch published output and the
  deployed URL, not source paths - verified, no changes needed there).
- scripts/validate_admin_render.sh: admin render-mode file paths now
  src/TaxBaik.Web.Client/...
- scripts/validate_kst_timestamps.sh: dropped deploy.sh from its target
  list - that script was removed in the prior cleanup commit (dead, no
  CI workflow referenced it) but this validator still expected it to exist.
- CLAUDE.md, docs/ENGINEERING_HARNESS.md, docs/ADMIN_PATTERN_CRITIQUE_WBS.md:
  updated project-structure diagram, dotnet run/build commands, and grep
  targets to the new src/ paths (also fixed a pre-existing stale path in
  ADMIN_PATTERN_CRITIQUE_WBS.md that still said TaxBaik.Web/Components/Admin
  from before that ever moved to TaxBaik.Web.Client).
- Added a Repo Root harness rule + Architecture Guardrail entries: new files
  belong under src/docs/tests/scripts/db/deploy, not loose at root; temp
  work stays outside the repo (or under a gitignored .scratch/) and is
  never committed.

Verified locally: dotnet build/test src/TaxBaik.sln (26/26 tests), and all
three scripts/validate_*.sh pass against the new layout.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

src/TaxBaik.Web.Client/Components/Admin/Forms/CompanyForm.razor

@@ -0,0 +1,88 @@
+@using TaxBaik.Application.Services
+
+<MudForm @ref="form">
+    <MudTextField @bind-Value="model.CompanyCode" Label="회사 코드"
+        Variant="Variant.Outlined" Class="mb-4" Required="true"
+        HelperText="영문/숫자, 최대 50자" />
+
+    <MudTextField @bind-Value="model.CompanyName" Label="회사명"
+        Variant="Variant.Outlined" Class="mb-4" Required="true" />
+
+    <MudTextField @bind-Value="model.ContactPerson" Label="담당자명"
+        Variant="Variant.Outlined" Class="mb-4" />
+
+    <MudTextField @bind-Value="model.Phone" Label="전화번호"
+        Variant="Variant.Outlined" Class="mb-4" />
+
+    <MudTextField @bind-Value="model.Email" Label="이메일"
+        Variant="Variant.Outlined" Class="mb-4" InputType="InputType.Email" />
+
+    <MudTextField @bind-Value="model.Memo" Label="메모"
+        Variant="Variant.Outlined" Lines="3" Class="mb-4" />
+
+    <MudCheckBox @bind-Checked="model.IsActive" Label="활성" Class="mb-4" />
+
+    <div class="d-flex gap-2">
+        <MudButton Variant="Variant.Filled" Color="Color.Primary" @onclick="HandleSubmit">
+            @ButtonText
+        </MudButton>
+        <MudButton Variant="Variant.Outlined" @onclick="OnCancel">취소</MudButton>
+    </div>
+</MudForm>
+
+@code {
+    [Parameter, EditorRequired]
+    public string ButtonText { get; set; } = "저장";
+
+    [Parameter]
+    public EventCallback<CompanyFormModel> OnSubmit { get; set; }
+
+    [Parameter]
+    public EventCallback OnCancel { get; set; }
+
+    [Parameter]
+    public CompanyFormModel? InitialData { get; set; }
+
+    private MudForm? form;
+    private CompanyFormModel model = new();
+
+    protected override void OnInitialized()
+    {
+        if (InitialData != null)
+        {
+            model = new CompanyFormModel
+            {
+                CompanyCode = InitialData.CompanyCode,
+                CompanyName = InitialData.CompanyName,
+                ContactPerson = InitialData.ContactPerson,
+                Phone = InitialData.Phone,
+                Email = InitialData.Email,
+                Memo = InitialData.Memo,
+                IsActive = InitialData.IsActive
+            };
+        }
+    }
+
+    private async Task HandleSubmit()
+    {
+        if (form == null)
+            return;
+
+        await form.Validate();
+        if (!form.IsValid)
+            return;
+
+        await OnSubmit.InvokeAsync(model);
+    }
+
+    public class CompanyFormModel
+    {
+        public string CompanyCode { get; set; } = "";
+        public string CompanyName { get; set; } = "";
+        public string? ContactPerson { get; set; }
+        public string? Phone { get; set; }
+        public string? Email { get; set; }
+        public string? Memo { get; set; }
+        public bool IsActive { get; set; } = true;
+    }
+}