docs(pi): unify split package trees; move live OMP pages to core

Two directories documented one concept (pi npm packages): top-level
packages/ (browser-use, permission-system) and pi/packages/ (peon,
web-access, subagents). Merged into pi/packages/ — one row per package
in a single index, detail pages kept as archive records. The root
index's 'OMP packages and skills' section was doubly wrong (packages/
was pi, not OMP); it becomes a Skills tooling section pointing at the
consolidated /skills/ tree.

Moved the two LIVE omp pages out of the retired-harness banner:
pi/statusline.md -> core/statusline.md, pi/subagent-limits.md ->
core/subagent-limits.md (both document omp behavior against
agent/config.yml + the installed bundle; pi/index.md itself admitted
the mis-shelf). Retargeted every inbound link (core/index, system/
dankserver, log x2, pi/index, settings x2, moved files' own xrefs).

Refs #29

omp-docs/index.md

@@ -31,9 +31,11 @@ CachyOS, skills tooling — each with its verified operational facts.
 The legacy pi agent configuration (~/.pi era): settings, models, packages,
 skills. Kept for reference; the live harness is OMP under `~/.omp`.
 
-## [OMP packages and skills](packages/index.md), [skills index](skills/index.md)
+## [Skills tooling](skills/index.md)
 
-Extensions and skills installed for the current OMP harness.
+The Agent Skills standard, the `skills` CLI, this fleet's store wiring, and
+the registries — for the live OMP harness. Pi-era packages are archived under
+[Pi-era agent setup](pi/index.md).
 
 ## [Core config](core/index.md)