chore(skills): wire agent/skills to the skills CLI global store

Retroactive provenance registration: the 10 pi-era skill snapshots are
byte-identical to upstream (38 skills mattpocock/skills + find-skills
vercel-labs/skills), now canonically installed at ~/.agents/skills with
store lockfile ~/.agents/.skill-lock.json (39 entries, folder hashes).

omp is not a skills-CLI agent id, so the omp tier becomes manual wiring:
replace the 10 tracked skill directories with symlinks into the store
and link the remaining 29 upstream skills the same way (39 links). The
repo now records the enabled set, never content; skills update -g
propagates through the links. managed-skills tier untouched.

Docs: skill-store-wiring.md (+index). Snapshot of the old real dirs at
/tmp/agent-skills-snap-20261018 for the transition window.

agent/skills/handoff

@@ -0,0 +1 @@
+/home/blank/.agents/skills/handoff

agent/skills/handoff/SKILL.md

@@ -1,16 +0,0 @@
----
-name: handoff
-description: Compact the current conversation into a handoff document for another agent to pick up.
-argument-hint: "What will the next session be used for?"
-disable-model-invocation: true
----
-
-Write a handoff document summarising the current conversation so a fresh agent can continue the work. Save to the temporary directory of the user's OS (`$TMPDIR`, else `/tmp`; `%TEMP%` on Windows) - not the current workspace.
-
-Include a "suggested skills" section in the document, naming which skills the next agent should call the Skill tool for.
-
-Do not duplicate content already captured in other artifacts (specs, plans, ADRs, issues, commits, diffs). Reference them by path or URL instead.
-
-Redact any sensitive information, such as API keys, passwords, or personally identifiable information.
-
-If the user passed arguments, treat them as a description of what the next session will focus on and tailor the doc accordingly.

agent/skills/handoff/agents/openai.yaml

@@ -1,5 +0,0 @@
-interface:
-  display_name: "Handoff"
-  short_description: "Compact a conversation into a handoff"
-policy:
-  allow_implicit_invocation: false