chore: 初始化 MCM/ICM Toolkit 仓库骨架

审查并精简 ChatGPT 的建库建议后落地的第一版骨架，只定接口不写实现。

- 建议审查：14 个包 → 7 个；约 250 个函数 → 约 40 个；5 个 Result 类 → 1 个
  （docs/01-suggestion-review.md）
- docs/：架构、路线图（含永久不做清单）、环境、Git 工作流、函数卡片模板
- src/mcm_toolkit/：core / data / stats / models / solve / decision / viz
  共 23 个模块，均为签名 + docstring + NotImplementedError
- tests/：9 个文件，其中 test_api_surface.py 已通过（20 passed）
- examples/ problems/ notebooks/ figures/ tables/ 骨架
- pyproject.toml（核心依赖 4 个 + 6 组 extras）、environment.yml
- scripts/：setup-venv.ps1（ASCII + LF）、setup-conda.ps1、doctor.ps1
- 环境：.venv（system-site-packages）与 conda 环境 mcm-toolkit 均已建好，
  数值栈版本与 base 完全对齐（numpy 2.4.6 / scipy 1.18.1 / pandas 3.0.6，MKL 后端）

scripts/setup-venv.ps1

@@ -0,0 +1,71 @@
+#Requires -Version 5.1
+<#
+.SYNOPSIS
+    Create .venv inside the repo and install mcm-toolkit in editable mode.
+
+.DESCRIPTION
+    Uses --system-site-packages so the venv reuses the scientific stack already
+    installed in Anaconda base. That makes the whole step OFFLINE: no package is
+    downloaded, yet numpy / scipy / pandas / matplotlib / sklearn / statsmodels /
+    networkx / sympy are all importable.
+
+    The editable install uses --no-deps --no-build-isolation: dependencies are
+    already provided by base, and pip must not go online for a build backend.
+
+    NOTE: this file is intentionally pure ASCII and UTF-8 without BOM.
+    Windows PowerShell 5.1 parses .ps1 as ANSI when there is no BOM, so non-ASCII
+    characters (e.g. Chinese) turn into illegal bytes and cause syntax errors.
+
+.PARAMETER Python
+    Interpreter used to create the venv. Default: D:\anaconda\python.exe
+
+.PARAMETER Recreate
+    Delete and recreate .venv if it already exists.
+
+.EXAMPLE
+    .\scripts\setup-venv.ps1
+#>
+[CmdletBinding()]
+param(
+    [string]$Python = 'D:\anaconda\python.exe',
+    [switch]$Recreate
+)
+
+$ErrorActionPreference = 'Stop'
+$repoRoot = Split-Path -Parent $PSScriptRoot
+$venvDir = Join-Path $repoRoot '.venv'
+
+if (-not (Test-Path -LiteralPath $Python)) {
+    $cmd = Get-Command python -ErrorAction SilentlyContinue
+    if (-not $cmd) { throw "Python interpreter not found: $Python" }
+    $Python = $cmd.Source
+    Write-Host "Using python from PATH: $Python" -ForegroundColor Yellow
+}
+
+if (Test-Path -LiteralPath $venvDir) {
+    if (-not $Recreate) {
+        Write-Host '.venv already exists. Use -Recreate to rebuild.' -ForegroundColor Yellow
+    } else {
+        Write-Host 'Removing existing .venv ...'
+        Remove-Item -LiteralPath $venvDir -Recurse -Force
+    }
+}
+
+if (-not (Test-Path -LiteralPath $venvDir)) {
+    Write-Host '[1/3] creating .venv (--system-site-packages, reuses Anaconda base) ...'
+    & $Python -m venv --system-site-packages --prompt 'mcm-toolkit' $venvDir
+    if ($LASTEXITCODE -ne 0) { throw 'venv creation failed' }
+}
+
+$venvPy = Join-Path $venvDir 'Scripts\python.exe'
+
+Write-Host '[2/3] editable install of mcm-toolkit (--no-deps --no-build-isolation) ...'
+& $venvPy -m pip install -e $repoRoot --no-deps --no-build-isolation --disable-pip-version-check
+if ($LASTEXITCODE -ne 0) { throw 'pip install -e failed' }
+
+Write-Host '[3/3] verifying ...'
+& $venvPy -c "import mcm_toolkit, numpy, scipy, pandas, matplotlib; print('mcm_toolkit', mcm_toolkit.__version__); print('numpy', numpy.__version__)"
+
+Write-Host ''
+Write-Host 'Done. Activate with:' -ForegroundColor Green
+Write-Host '    .\.venv\Scripts\Activate.ps1'