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/core/settings.md

@@ -222,7 +222,7 @@ Currently installed:
 | `@xynogen/pix-ls` | 0.2.1 | Directory listing |
 | `@xynogen/pix-edit` | 0.2.1 | File editing utilities |
 
-See [packages](../packages/index.md) for full package documentation.
+See [Pi Packages](/pi/packages/index.md) for full package documentation.
 
 ---
 
@@ -236,5 +236,5 @@ When `lastChangelogVersion` is behind pi's internal version, pi prompts for migr
 
 - [pi](../pi/index.md) — Pi configuration overview
 - [[models|models]] — Provider and model definitions
-- [packages](../packages/index.md) — Installed package documentation
+- [Pi Packages](/pi/packages/index.md) — Installed package documentation
 - [[skills|skills]] — Installed skill documentation