docs+publisher: the subos example was nested under the wrong table, and deps emits no edge by design

The 2.13 example put `subos = "dev"` after `[xlings.workspace]`, which in TOML
makes it `xlings.workspace.subos` — a key nothing reads. Two blocks, each under
the table it belongs to.

The emitter gains the reason it skips a package still on `deps`: that key is
host-resolved at load, so the per-platform declaration a descriptor needs is
already gone, and writing the host's answer into all three blocks would be the
machine-dependent descriptor the function exists to avoid.

Author: speak-agent

.agents/docs/2026-09-03-xlings-workspace-as-the-one-table.md

@@ -315,6 +315,12 @@ struct XlingsConfig {
 
 `resolve_host_value` already knows which platform each value belongs to.
 
+A package still on `deps` emits no edge, as before. Its declaration is
+host-resolved at load, so the per-platform information a descriptor needs is
+gone by the time the emitter runs, and writing the host's answer into all three
+blocks would be the machine-dependent descriptor this section exists to
+prevent. The advisory tells its author how to obtain one.
+
 ## 6. Documentation
 
 **`docs/05` §2.13** gains the inheritance rule as a table, next to

docs/05-mcpp-toml.md

@@ -1875,7 +1875,10 @@ picolibc-riscv          = "xim:1.8.12"     # namespace on the version
 "xim:qemu-user-aarch64" = "7.2.0"          # or on the key - quotes required
 code                    = ""               # present; version unconstrained
 llvm                    = { macosx = "20", default = "22" }
+```
 
+```toml
+[xlings]
 subos = "dev"                      # a named, isolated environment
 ```
 

docs/zh/05-mcpp-toml.md

@@ -1600,7 +1600,10 @@ picolibc-riscv          = "xim:1.8.12"     # 命名空间写在版本上
 "xim:qemu-user-aarch64" = "7.2.0"          # 或写在键上 —— 必须带引号
 code                    = ""               # 存在即可,版本不限
 llvm                    = { macosx = "20", default = "22" }
+```
 
+```toml
+[xlings]
 subos = "dev"                      # 指名的隔离环境
 ```
 

src/pm/publisher.cppm

@@ -133,6 +133,13 @@ std::string platform_block(std::string_view version, const ReleaseInfo::PerPlatf
 // discarded two of the three. Emitting from the host-resolved list instead
 // would produce a descriptor whose edges depend on which machine packed it,
 // and nothing downstream could tell.
+//
+// ⚠️ A package still on the superseded `[xlings] deps` emits NO edge, exactly
+// as before. That is not an oversight: `deps` is resolved for the host at
+// load, so the per-platform declaration a descriptor needs is already gone by
+// the time this runs, and writing the host's answer into all three blocks
+// would be the machine-dependent descriptor this comment rejects. The
+// advisory that key raises tells its author how to obtain an edge.
 std::string platform_deps_block(
     const std::map<std::string, std::vector<std::string>>& byPlatform,
     std::string_view platform)