feat: add taskbook/proposal/midterm documents via doctype option

[RizhongLin]

概要 | Summary

请简要描述本 PR 所做的工作 | Brief description of the changes:

• 新增 doctype 类选项（thesis（默认）/ taskbook / proposal / midterm），与既有 degree / field / algo 选项模式一致。默认值不变，main.tex 的论文正文流程不受影响；未知取值回退到 thesis 并给出 \ClassWarning。同时新增 \iftongjithesis@form 条件，表示“doctype 为 3 份表格之一”，供三者行为一致处使用。
  New doctype class option (thesis (default) / taskbook / proposal / midterm), following the existing degree / field / algo pattern. The default is unchanged, so main.tex's thesis flow is unaffected; an unrecognized value falls back to thesis with a \ClassWarning. Also adds an \iftongjithesis@form conditional meaning "doctype is one of the three forms", for the many places where all three behave alike.

• 新增 3 个可独立编译的行政文档入口：taskbook.tex（任务书）、proposal.tex（开题报告）、midterm.tex（中期报告）。三者与正文共用 chapters/metadata.tex 的学院/专业/学生/课题信息（指导教师在 3 份表格中均为手写签字位，不预填），结构一致：\input{chapters/metadata} → \MakeDocument（按 doctype 分派到 \MakeTaskBook / \MakeProposal / \MakeMidterm）→ \input{chapters/{taskbook,proposal,midterm}_body}，无 frontmatter/mainmatter/参考文献阶段。正文段落内容采用与 chapters/appendix.tex 一致的“编辑替换示例文字”模式。
  Three new standalone entry points — taskbook.tex, proposal.tex, midterm.tex — sharing the school/major/student/topic fields from chapters/metadata.tex (the advisor is a handwritten signature slot on all three forms and is never prefilled). All three have the same shape: \input{chapters/metadata} → \MakeDocument (dispatching to \MakeTaskBook / \MakeProposal / \MakeMidterm by doctype) → \input{chapters/{taskbook,proposal,midterm}_body}, with no frontmatter/mainmatter/bibliography stages. Body content follows the same edit-the-sample-text pattern as chapters/appendix.tex.

• 新增 .cls 排版原语，使 chapters/*_body.tex 只写内容、不手动设置字体字号：\tjformtable（无边框信息表，仅靠下划线呈现填空位置）、\tjformsection / \tjformsubsection（一/二级分节标题）、\tjformnotice + tjformnoticebody（说明页标题与条目）、\tjformlabel（审核意见框字段标签）、\tjformsignature（签字行）、\tjreviewbox（审核意见方框）、\tjdateblank、\tjnumline，以及 \tjformnote / \tjformhint 两级灰度批注——前者为成稿时应删除的说明文字，后者为保留在表格中的内容提示。
  New .cls primitives so chapters/*_body.tex carries content only, never manual font/size switches: \tjformtable (borderless info table, fill-in positions shown by underlines alone), \tjformsection / \tjformsubsection (level-1/2 headings), \tjformnotice + tjformnoticebody, \tjformlabel (review-box field labels), \tjformsignature (signature lines), \tjreviewbox, \tjdateblank, \tjnumline, and two semantically distinct gray annotations — \tjformnote for text to delete before finalizing, \tjformhint for guidance that stays on the form.

• 三份表格的字体字号按撰写规范设定：封面大标题小初号黑体，课题信息表四号宋体；一级分节标题四号黑体，开题报告二级标题小四号黑体；审核意见框内的字段标签与签字行（含年/月/日）为小四号黑体，同框内的灰色提示与“同意/不同意”复选框行保持宋体；任务书正文末尾签字行为四号黑体；中期报告“填写说明”标题小二号黑体加粗、条目四号，封面填表日期三号。\tjformtable 显式声明 \songti，不依赖文档默认字族。
  Typography follows the writing spec throughout: cover titles 小初黑体 and subject tables 四号宋体; level-1 headings 四号黑体 and the proposal's level-2 headings 小四黑体; review-box field labels and signature lines (including 年/月/日) 小四黑体, while the gray hints and the 同意/不同意 checkbox line inside the same box stay 宋体; the task book's trailing signature line 四号黑体; the mid-term report's 填写说明 heading 小二黑体加粗 with 四号 items, and its cover date 三号. \tjformtable declares \songti explicitly rather than inheriting the document default.

• \taskbookperiod{起始年}{月}{日}{截止年}{月}{日}（在 chapters/metadata.tex 中设置）经 pgfcalendar 由起讫日期自动换算任务书周数（向上取整），无需手动填写；起讫日期越序时报 \ClassError。未调用时各字段保持空白下划线。
  \taskbookperiod{...} (set in chapters/metadata.tex) derives the task book's week count from the date range via pgfcalendar (ceiling-rounded), so it is never entered by hand; an inverted range raises a \ClassError. If never called, the fields render as blank underlines.

• 复选框字形改由 \tj@checkboxglyph 统一生成：amssymb 的 $\square$ 明显小于周围汉字，故按当前字号缩放至与汉字等高，勾号限高后居中叠印在方框内，下沉量作用于整组；\mbox 包裹使复选框在段首也能正确渲染。新增通用的 \tjcheckboxeq{当前值}{目标值} 与 \midtermdecision{agree|disagree}，供中期报告“专业审核意见”按需勾选（默认留空，供打印后手写）。本项亦改变论文信息说明页“成果类型”复选框的呈现。
  Checkbox glyphs are now produced by a single \tj@checkboxglyph: amssymb's $\square$ is noticeably smaller than surrounding CJK, so the box is scaled to match, the mark is height-limited and overprinted centered inside it, and the vertical shift applies to the whole group. An \mbox wrapper keeps the glyph correct at paragraph start. Adds generic \tjcheckboxeq{current}{target} and \midtermdecision{agree|disagree} for the mid-term report's 专业审核意见 box (blank by default, for handwriting after printing). This also changes how the thesis info page's 成果类型 checkbox renders.

• 三份表格使用独立页边距（A4，上 2.3cm／下 1.0cm／左右各 3.17cm），与论文正文的装订页边距不同；且全程不显示装订线——三者是单独打印/提交的行政表格，与 \MakeCover / \MakeInfoPage（仅在封面页关闭、其后随正文恢复）形成对比。
  The three forms use their own page geometry (A4, top 2.3cm / bottom 1.0cm / left and right 3.17cm), distinct from the thesis's binding margins, and never draw the binding line — they are separately printed and submitted, unlike \MakeCover / \MakeInfoPage, which disable it for the cover page only and restore it for the body that follows.

• Makefile / make.bat 新增 taskbook / proposal / midterm / forms 目标，clean / cleanall 同步覆盖新产物；CI 新增 build-forms job（Linux + xelatex，每份文档一个矩阵项）编译全部 3 个文档，test-summary、collect-pdfs 相应更新 needs。
  Makefile / make.bat gain taskbook / proposal / midterm / forms targets, with clean / cleanall covering the new outputs; CI gains a build-forms job (Linux + xelatex, one matrix leg per document) compiling all three, and test-summary / collect-pdfs were updated accordingly.

• 全仓中文行文的引号统一为成对全角弯引号 “” / ‘’（代码/verbatim/数学撇号除外），并在 AGENTS.md 记录该约定。
  Chinese prose across the repo now uses paired curly “” / ‘’ (code/verbatim/math-prime excepted), with the convention recorded in AGENTS.md.

• 文档同步更新：README.md / README-EN.md / CONTRIBUTING.md / AGENTS.md / chapters/01_guide.tex 记录新选项、3 份新文档、选项排序，以及 *_body.tex 中可用的排版命令。
  Docs updated across README.md / README-EN.md / CONTRIBUTING.md / AGENTS.md / chapters/01_guide.tex to cover the new option, the three new documents, option ordering, and the commands available in *_body.tex.

设计取舍 | Design decisions:

• 键名选用 doctype 而非泛化的 type，以避免与既有的 \infotype{thesis|design|engineering} 宏（同一类中另一条“类型”轴）冲突。
  Chose doctype over a generic type to avoid colliding with the existing \infotype{thesis|design|engineering} macro — a different, pre-existing "type" axis in the same class.

• 表格封面沿用本模板论文封面 \MakeCover 的版式（整体居中、每字段独占一行、\ulinecentered 定宽下划线，填写前后长度与位置一致、内容过长自动换行），而非逐像素复刻某一份 Word 渲染结果；字体则按各自规范取值，故两者共用版式而不共用字体。
  Form covers reuse this template's own \MakeCover layout (centered, one field per row, fixed-width \ulinecentered underlines that keep length and position whether filled or blank, wrapping when long) rather than pixel-matching any single Word rendering. Typefaces follow each document's own spec, so the two share layout but not typeface.

• 封面大标题用半角括号（\tjformheadertext），使“开题报告 / 中期报告”标题在小初号下仍能单行排下；正文各处仍用全角括号的 \tjheadertext。
  Cover titles use half-width parentheses (\tjformheadertext) so the 开题报告 / 中期报告 headings still fit on one line at 小初; body text keeps the full-width \tjheadertext.

• 一/二级分节标题均为手工编号，不计入目录、不参与章节编号：列表环境无法把序号本身也置为黑体，且会额外引入列表缩进。
  Level-1 and level-2 headings are manually numbered and enter neither the TOC nor the chapter numbering: a list environment cannot set the label itself in 黑体, and would add its own indentation.

检查清单 | Checklist

• 已通读贡献指南。
• 如涉及模板功能变更，已编写注释并更新对应文档。
• 如涉及模板功能变更，已尽可能在各平台上进行测试。
  • CI 覆盖：build（3 OS × {XeLaTeX, LuaLaTeX}）、build-variants、新增的 build-forms（3 份文档各一个矩阵项）、test-summary、collect-pdfs、package；结果以本 PR 的 Checks 页为准。
  • 本地：make（默认选项）与 make taskbook / make proposal / make midterm 均编译通过，3 份表格零 Overfull/Underfull 警告。
  • 选项组合：doctype={taskbook,proposal,midterm} × field=humanities 均编译通过，封面标题与分节标题按 field 正确切换且仍单行排下。
  • 复选框：\midtermdecision{agree} 在段首正确渲染（勾号完整落在方框内），信息说明页 \tjcheckbox 的判断逻辑不变。
  • 逐页目视核对全部封面与正文页（课题信息表、签字区、审核意见框、复选框、起讫时间下划线）。

已知事项 | Known items:

• main.tex 相对 dev 新增若干 Underfull \hbox 提示，全部位于 chapters/01_guide.tex：新增说明段落中的长 \verb 记号不可断行，两端对齐时行内空格被拉伸。仅影响手册排版观感，不影响版面结构。
  Relative to dev, main.tex gains a number of Underfull \hbox messages, all in chapters/01_guide.tex: long \verb tokens in the new documentation cannot be broken, so justified lines stretch their interword spaces. Cosmetic to the manual only; no structural effect.

关联 Issue | Related Issues

无 | None.

截图 | Screenshots

模板输出有变化：新增 3 份文档，并改变了论文信息说明页复选框的呈现。各文档编译产物可从本 PR 的 CI collect-pdfs artifact 下载核对。
The template output changes: three new documents, plus a different rendering of the thesis info page's checkbox. Compiled PDFs for every document can be downloaded from this PR's CI collect-pdfs artifact.