headscale leaves the baseline, and offscale gets a design doc

first step of extracting headscale into a plugin. CORE_PROCESSES is five now,
and the catalogue.test CORE[] mirror follows it — not optional, since that list
asserts "the catalogue must not offer a core process" and would have blocked
adding offscale to the catalogue later.

the local generated ecosystem file lost its entry too, and officer-headscale was
stopped and deleted from pm2 by hand. the platform still mounts /api/headscale
and still declares the headscale and vpn capabilities, so the feature is
present-but-unavailable rather than gone.

docs/offscale-plugin.md is a live document for the rest of it. what it records
that nothing else does: core is now `officer` alone and everything else is a
plugin; routes are /api/<app-name> for ours and /api/p/<creator>/<app-name> for
third parties, derived by one function so the two can never become two systems;
tables stay in public with an app-name prefix; mounting becomes genuinely
dynamic, which retires the "every route stays mounted" premise and relocates
assertCapabilityTotality from a boot check to a per-mount transaction.

it also records a rejected experiment with evidence — a postgres schema per
plugin works completely, including cross-schema FK, idempotent push and
DROP SCHEMA CASCADE as uninstall — and the reason not to: drizzle-kit 0.31.8
needs schemaFilter naming every schema, contradicting its own docs, and without
it push reports "No changes detected" and creates nothing. a plugin install that
reports success and makes no tables is the exact failure shape we have hit three
times this week.

and /api/vpn is dead: no caller in the mobile monorepo, none in the web app, no
grants in the database. offscale is permanently standalone, so it never comes
back. the invite flow is unaffected — the phone claims from the Companion, not
from officer.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

scripts/setup/officer-setup/lib/services.sh

@@ -44,7 +44,6 @@ CORE_PROCESSES=(
   "officer-claude-code|bun|run src/servers/sidecar/claude/user-instance.ts"
   "officer-opencode|bun|run src/servers/sidecar/opencode/index.ts"
   "officer-pty|node|src/servers/sidecar/pty/index.mjs"
-  "officer-headscale|bun|run src/servers/sidecar/headscale/index.ts"
 )
 
 write_ecosystem() {