docs(newos4): merge the two shell-composition skills into one seeded skill (v4.6.65)

Packet 9. `terminal-commands-silently-failing` and `command-composition-rules` described
the same bug family from two angles, and since v4.6.58 both were describing behaviour
that is now refused outright.

- new seeded skill `command-composition-rules` in skill-pack-core's _buildSkills():
  the rule, why the refusal exists (with the 42-42 / 34k-a measurement), what works
  (one command per call, wc multi-path, interactive-only pipes, quoted operators),
  how to verify a plausible-looking result, and the pitfalls
- its History section names both retired skills so a reader arriving from either
  search finds the surviving one
- mirrored onto disk as skills/command-composition-rules.md + .json and added to
  skills/index.json (18 entries) so the repo copy matches what sessions receive

Verified live on v4.6.65: seeding reported 15 skills (was 14), the file and index
entry exist in the fresh VFS, and the natural-language query "does the terminal have
a shell and what is refused" returns command-composition-rules first (13.78, 3/4).

1 files changed, 13 insertions, 25 deletions

diff --git a/skills/index.json b/skills/index.json
index 5f8d78a..4bce206 100644
--- a/skills/index.json
+++ b/skills/index.json
@@ -108,7 +108,7 @@
   },
   "module-editing-workflow": {
     "name": "module-editing-workflow",
-    "description": "Step-by-step procedure for editing a WebX11 module: view → edit → test → keep or reload",
+    "description": "Step-by-step procedure for editing a WebX11 module: view \u2192 edit \u2192 test \u2192 keep or reload",
     "tags": [
       "modules",
       "editing",
@@ -121,7 +121,7 @@
   },
   "vfs-content-search": {
     "name": "vfs-content-search",
-    "description": "Find files in the VFS by semantic concept (NVFS) or by content keyword (grep) — decision table",
+    "description": "Find files in the VFS by semantic concept (NVFS) or by content keyword (grep) \u2014 decision table",
     "tags": [
       "vfs",
       "search",
@@ -148,7 +148,7 @@
   },
   "vfs-path-normalize": {
     "name": "vfs-path-normalize",
-    "description": "Strip trailing slashes from VFS paths before API calls — prevents /skills/ vs /skills resolution failures",
+    "description": "Strip trailing slashes from VFS paths before API calls \u2014 prevents /skills/ vs /skills resolution failures",
     "tags": [
       "vfs",
       "utility",
@@ -223,30 +223,18 @@
     "created": "2026-06-05T22:10:06.670Z",
     "updated": "2026-06-05T22:13:42.539Z"
   },
-  "skills-system-guide": {
-    "name": "skills-system-guide",
-    "description": "How to use the skills system: load, create, patch, list, and audit skills for persistent procedural memory",
-    "tags": [
-      "skills",
-      "system",
-      "meta"
-    ],
-    "category": "system",
-    "created": "2026-06-05T22:10:06.669Z",
-    "updated": "2026-06-05T22:13:42.539Z"
-  },
-  "webdav-operations": {
-    "name": "webdav-operations",
-    "description": "How to use WebDAV cloud storage for backup, file sync, and remote file access",
+  "command-composition-rules": {
+    "name": "command-composition-rules",
+    "description": "The terminal has no shell: what is refused, what works, and how to verify a result that looks plausible",
     "tags": [
-      "webdav",
-      "cloud",
-      "backup",
-      "sync",
-      "storage"
+      "terminal",
+      "shell",
+      "composition",
+      "safety",
+      "agent"
     ],
     "category": "system",
-    "created": "2026-06-05T22:10:06.670Z",
-    "updated": "2026-06-05T22:13:42.539Z"
+    "created": "2026-10-23T16:27:07.000Z",
+    "updated": "2026-10-23T16:27:07.000Z"
   }
 }
\ No newline at end of file