chore(spec+checker): cleanup pass — trim docs, reorg Courseware, covers-as-data, fold DanglingReference (ADR-0012)

Spec母本噪音清理 + 一处 spec↔impl 对齐 + 一处契约自洽修正。

Part A — spec doc 瘦身:每条 doc 收到"语义点 + 标签 + ADR ref + 承载性 why",
把跨文件复读的方法论(element-kind 开放性对比、likec4 画不出、分歧点测试)上移到
module header。OPEN 框架保持清晰(RunState/Capability 完整性仍明示须 surface)。

Part B — Courseware/ 由 10 文件平铺重组为 Model/ Export/ Check/ Open/ 四子命名空间
(namespace Spec.Courseware 不变,零引用改动)+ 四个子 aggregator。lake build 绿(24 jobs)。

Part C — 渲染覆盖落为数据(ADR-0011 对齐):去掉 cph-check 里硬编码的
COVERED_TARGETS,改读 TargetConfig.covers。cph-model 新增 covers: Option<Vec<String>>
(None=未声明,由 cph-check 默认为全部 known kinds;显式 [] 表示不覆盖任何 kind)。
新增 3 个覆盖行为测试。

ADR-0012 — DanglingReference 退役(诊断 7→6 类):其两种情形(未解析 @ref、越界/缺失
相对 import)都是 typst 编译期失败,归 typstCompile。同步移除 Oracle.refsResolve
(被 compiles 蕴含),Legal 少一个合取项。impl 删去从未被发射的 DiagCode::DanglingReference,
闭合 named-but-unemitted 的 spec↔impl 缝。ADR-0010 加修订指针。

OPEN 点(RunState/Capability 完整性、QuestionBank、Course)按既定纪律保持 OPEN,本次
只改善其框架措辞,不决策。

验证:spec lake build 绿;cargo test 全绿(含新增覆盖测试);clippy 静默;
TH-141 check 0 errors/0 warnings 无回归。

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

crates/cph-check/src/lib.rs

@@ -17,15 +17,11 @@ use cph_typst::Engine;
 /// The default render target when a lesson declares no `[targets.*]` at all.
 const DEFAULT_TARGET: &str = "student";
 
-/// The render targets the MVP render package actually covers (student handout +
-/// teacher plan). Used by the render-coverage rule (phase (e)).
-const COVERED_TARGETS: &[&str] = &["student", "teacher"];
-
 /// Severity of the render-coverage ("element ignored under a target") diagnostic.
 ///
 /// **PINNED to `warning` by the contract.** Mirrors the Lean master's
 /// `Spec.Courseware.renderIgnoredSeverity : Severity := .warning`
-/// (`spec/Spec/Courseware/Diagnostic.lean`), itself citing ADR-0005: when a
+/// (`spec/Spec/Courseware/Check/Diagnostic.lean`), itself citing ADR-0005: when a
 /// `(kind, target)` pair has no render rule the checker reports that the element
 /// is ignored under that target and **does not block the export**. Naming the
 /// severity as a const makes "it is a warning, not an error" a greppable,
@@ -62,7 +58,7 @@ impl CheckReport {
     /// Whether any collected diagnostic is `Error`-severity.
     ///
     /// **Legality decision (spec alignment).** `!has_errors()` is the
-    /// implementation of `Spec.Courseware.Legal` (`spec/Spec/Courseware/Diagnostic.lean`):
+    /// implementation of `Spec.Courseware.Legal` (`spec/Spec/Courseware/Check/Diagnostic.lean`):
     /// a lesson is *legal* iff its diagnostics contain no error-level diagnostic
     /// (warnings are non-blocking — see `Severity` / ADR-0010). There is no CI
     /// gate enforcing this alignment (repo constitution); it is kept greppable
@@ -93,7 +89,8 @@ impl CheckReport {
 ///   declared `lesson.targets` (defaulting to `"student"` if none), deduping
 ///   identical diagnostics across targets.
 /// - **(e) render-coverage** — a `warning` (never an error) for each
-///   `(kind, target)` lacking a render rule. Runs regardless of (d) gating.
+///   `(kind, target)` the target's `covers` declaration does not include. Runs
+///   regardless of (d) gating.
 ///
 /// The engine is taken as a parameter so the caller owns it (and tests can
 /// inject `Engine::with_render_dir`).
@@ -259,14 +256,17 @@ fn compile_targets(lesson: &cph_model::Lesson) -> Vec<&str> {
 }
 
 /// Phase (e): for each `(part.kind, target)` over the lesson's declared targets,
-/// emit a `RenderIgnored` **warning** when the pair has no render rule.
+/// emit a `RenderIgnored` **warning** when the target does not cover that kind.
 ///
-/// The render matrix lives in the render package and is not introspectable from
-/// Rust in the MVP, so coverage is defined operationally: a kind is covered when
-/// it is a known stdlib kind (`known`) AND the target is one the render package
-/// handles (`COVERED_TARGETS` = student/teacher). A declared target outside that
-/// set, or a kind not in the known set, yields the warning. Parts already broken
-/// in (b) (missing folder / unknown kind) are skipped — they are reported there.
+/// Coverage is the per-target **declaration** ADR-0011 pinned (and the spec's
+/// `RenderConfig.covers k t` in `Export/Render.lean`): a target's
+/// `cph_model::TargetConfig::covers` lists the kinds it renders. A used kind not
+/// in that list draws the warning. An **absent** `covers` (the loader's `None`)
+/// is resolved here — the orchestrator owns the kind universe via `cph-schema` —
+/// to "covers all known kinds", so an undeclared target is fully covering rather
+/// than covering nothing. (An explicit `covers = []` stays empty: it covers
+/// nothing on purpose.) Parts already broken in (b) (missing folder / unknown
+/// kind) are skipped — they are reported there.
 fn render_coverage(lesson: &cph_model::Lesson, known: &[&str]) -> Vec<Diagnostic> {
     let mut out = Vec::new();
     // De-dupe (kind, target) pairs so we emit one warning per pair, not per part.
@@ -278,7 +278,13 @@ fn render_coverage(lesson: &cph_model::Lesson, known: &[&str]) -> Vec<Diagnostic
             continue;
         }
         for target in &lesson.targets {
-            let covered = COVERED_TARGETS.contains(&target.name.as_str());
+            // Resolve the coverage set: an absent declaration defaults to the
+            // full known-kind universe; an explicit list (possibly empty) is
+            // taken verbatim.
+            let covered = match &target.covers {
+                None => true,
+                Some(kinds) => kinds.iter().any(|k| k == &part.kind),
+            };
             if covered {
                 continue;
             }
@@ -290,12 +296,12 @@ fn render_coverage(lesson: &cph_model::Lesson, known: &[&str]) -> Vec<Diagnostic
             let mut d = Diagnostic::warning(
                 DiagCode::RenderIgnored,
                 format!(
-                    "kind '{}' has no render rule for target '{}'; it will be omitted from that export",
+                    "kind '{}' is not covered by target '{}'; it will be omitted from that export",
                     part.kind, target.name
                 ),
             )
             .with_hint(format!(
-                "add a render rule for kind '{}' under target '{}', or remove the target",
+                "add '{}' to `covers` under target '{}', or remove the target",
                 part.kind, target.name
             ));
             // Pin the severity via the named contract const. `Diagnostic::warning`