skills: trim two descriptions to a routing sentence, and assert their pointers

Every skill's name and description sit in the system prompt of EVERY request --
that block is the routing index -- while bodies are fetched on demand through
the read tool. Measured on this device: 24 discoverable skills cost 10,609
description chars (~2,652 tokens) per request, against 474,656 chars of bodies
(~119k tokens) that cost nothing until used. Bodies are 45x the descriptions,
which is what the spec's 1024-char description limit is protecting.

credential-incident-response (1022, two characters under the limit) and
pi-devbox-environment (923) were each carrying a table of contents of what
their body covers. Trimmed to what a description is actually for -- answering
"should I load this?" -- reclaiming 1,087 chars (~271 tokens) of permanent
context. 4,154 -> 3,067 across the five baked skills.

WHY ONLY THESE TWO. Both are named BY PATH from the always-loaded managed
block, so neither depends on description-matching to be found. pi-extensions is
left alone deliberately: check-skill-floor.sh compares the vendored copy to the
package repo by DIRECTORY HASH, so trimming ours alone registers as drift and
turns that gate red; and it is the one skill that also ships in the skillset
repo, where it runs on hosts with no pi-devbox managed block and genuinely needs
its description. pi-devbox-firstboot stays fuller than needed because it is the
skill a device with nothing else has to find.

NOTHING WAS DELETED, ONLY RELOCATED -- and that was checked rather than assumed:
all 18 enumerated items were confirmed present in the bodies BEFORE cutting
(frontmatter stripped, so the description's own line could not score its own
claim), and `git diff --stat` confirms both bodies are byte-identical.

THE TRIM CREATES A DEPENDENCY, SO IT IS NOW ASSERTED. smoke-test.sh checks both
pointers by path, next to the firstboot one. The premise of the cut is "the
block names them", which holds only while those lines exist -- reword the block,
drop a pointer, and the skill silently stops being reachable for a device that
did not already know it was there. Verified discriminating: a reworded block
fails the grep.

An instrument failure caught on the way, and the reason the coverage check was
re-run: my first pass used `grep -E 'a\|b'`, where \| is a LITERAL pipe in ERE,
so 8 of 18 items read as 0 hits. Every zero was a pattern containing \| and
every non-zero lacked one -- that correlation, not the content, was the finding.
With real alternation all 18 are present.

Loader re-verified on both trimmed skills: rc=0, no skill diagnostics.

scripts/smoke-test.sh

@@ -304,6 +304,17 @@ run "mempalace session-start pointer merged into global AGENTS.md" \
 # rewording the paragraph must not be able to silently break the link.
 run "firstboot skill pointer merged into global AGENTS.md" \
     "grep -q 'pi-devbox-firstboot/SKILL.md' /opt/pi-toolkit/pi-global-AGENTS.md"
+# Same path assertion for the two skills whose descriptions were deliberately
+# TRIMMED to a routing sentence. Their frontmatter no longer enumerates what
+# they cover, on the explicit premise that this block names them by path and so
+# they never depend on description-matching to be found. That premise is only
+# true while these lines exist, which is exactly why it is asserted rather than
+# trusted: reword the block, drop a pointer, and the skill silently stops being
+# reachable for a device that did not already know it was there.
+run "pi-devbox-environment pointer merged into global AGENTS.md" \
+    "grep -q 'pi-devbox-environment/SKILL.md' /opt/pi-toolkit/pi-global-AGENTS.md"
+run "credential-incident-response pointer merged into global AGENTS.md" \
+    "grep -q 'credential-incident-response/SKILL.md' /opt/pi-toolkit/pi-global-AGENTS.md"
 # Vendored fallback skills (so a no-skillset container still resolves the
 # AGENTS.md 'read the pi-extensions skill' pointer).
 run "image-baked pi-extensions fallback skill" \