Feat v0.3.8 distribution (#21)

Bundled packages auto-install on first boot for zero-config first run.
Builder image for faster custom builds. Per-environment allowlists for
K8s/Helm (dev=all, test=all, prod=skip).

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

server/database/migrations/postgres/003_packages.sql

@@ -24,7 +24,7 @@ CREATE TABLE IF NOT EXISTS packages (
     schema_version INTEGER NOT NULL DEFAULT 0,
     package_settings JSONB NOT NULL DEFAULT '{}',
     source       TEXT NOT NULL DEFAULT 'core'
-                 CHECK (source IN ('core', 'builtin', 'extension', 'registry')),
+                 CHECK (source IN ('core', 'builtin', 'extension', 'registry', 'bundled')),
     installed_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),
     updated_at   TIMESTAMPTZ NOT NULL DEFAULT NOW()
 );

server/database/migrations/postgres/012_bundled_source.sql

@@ -0,0 +1,6 @@
+-- 012_bundled_source.sql — v0.3.8
+-- Adds 'bundled' to the packages.source CHECK constraint for auto-installed packages.
+
+ALTER TABLE packages DROP CONSTRAINT IF EXISTS packages_source_check;
+ALTER TABLE packages ADD CONSTRAINT packages_source_check
+    CHECK (source IN ('core', 'builtin', 'extension', 'registry', 'bundled'));