docs: site build also adds a missing label; the brief and the command line say so

.abcd/development/brief/04-surfaces/22-site.md

@@ -14,7 +14,8 @@ to remember to update it.
 
 The bare form is **strictly read-only**: it reports what the repository has
 declared and what the output directory holds. The build is the render, and it writes
-only inside the directory it is given. The check that gates a rendered tree is the site
+inside the directory it is given, and outside it only the missing-label completion
+of the interface-string file (below). The check that gates a rendered tree is the site
 target of the one lint ([`16-lint.md`](16-lint.md), itd-2609212130136102): it
 renders first when the directory holds no `index.html` — the one write path
 besides the build, confined to the same directory. Bare `abcd lint` runs the

.abcd/development/release/surface.json

@@ -2738,7 +2738,7 @@
     {
       "path": "abcd site build",
       "hidden": false,
-      "sentence": "Render the website into the output directory: Writes only inside that directory; refuses a non-empty directory it did not write.",
+      "sentence": "Render the website into the output directory: Writes there, plus a missing label into site-src/ui.json; refuses a non-empty directory it did not write.",
       "flags": [
         {
           "name": "commit",

docs/reference/cli/commands.md

@@ -2981,7 +2981,7 @@ Report what the website declares and what was built: Writes nothing; refuses any
 
 #### `abcd site build`
 
-Render the website into the output directory: Writes only inside that directory; refuses a non-empty directory it did not write.
+Render the website into the output directory: Writes there, plus a missing label into site-src/ui.json; refuses a non-empty directory it did not write.
 
 **Usage:** `abcd site build [flags]`
 

internal/core/surface/sentences.go

@@ -323,7 +323,7 @@ var sentences = map[string]string{
 	"abcd site": "Report what the website declares and what was built: " +
 		"Writes nothing; refuses any argument.",
 	"abcd site build": "Render the website into the output directory: " +
-		"Writes only inside that directory; refuses a non-empty directory it did not write.",
+		"Writes there, plus a missing label into site-src/ui.json; refuses a non-empty directory it did not write.",
 	"abcd site setup": "Take the website from this checkout to a live address: " +
 		"Writes its files, and the forge and host changes once confirmed; refuses a folder abcd does not manage.",
 

internal/surface/cli/helpgroups.go

@@ -142,8 +142,9 @@ var helpPlacements = map[string]helpPlacement{
 	"intent prepass": {page: "commands/intent.md"},
 
 	// itd-146 decision 2 files drain under records, but the person's list is at
-	// its fifteen-verb ceiling, and until the run is built the verb's one form
-	// is a dry run an agent reads. Listed here until the product thinker rules.
+	// its fifteen-verb ceiling, and each run invocation performs one move and
+	// names the run an agent drives with `implement step`, so an agent reads it
+	// either way. Listed here until the product thinker rules.
 	"drain": {group: groupAgents, page: "commands/drain.md"},
 }