Initial import: shopdb-flask multi-site asset platform

Flask + Vue rewrite of the classic-ASP shopdb, built as a plugin
framework so sister GE Aerospace sites can adopt it. Product version
0.7.0-pre-0.8.0, plugin contract 0.11.0, 966 backend tests.

Key entry points:
- docs/INSTALL-WINDOWS-IIS.md - tested Windows + IIS install runbook
  (own-site and subpath deployment methods)
- docs/PILOT-DEPLOY.md - production pilot: stand up + import + verify
- docs/IMPORT-API.md - schema-agnostic legacy data import contract
- scripts/site_imports/wjf/ - West Jefferson reference import loader
- docs/adr/ - twelve accepted architecture decision records

plugins/knowledgebase/migrations/env.py

@@ -0,0 +1,14 @@
+"""Alembic environment for the knowledgebase plugin migration chain.
+
+Delegates to the shared runner in shopdb.plugins.alembic_template, which
+filters the metadata to this plugin's tables and drives Alembic against the
+per-plugin version table alembic_version_knowledgebase. See ADR-008 for the
+ownership cutover between the core chain and per-plugin chains.
+"""
+import os
+
+os.environ['PLUGIN_NAME'] = 'knowledgebase'
+
+from shopdb.plugins.alembic_template import run_migrations  # noqa: E402
+
+run_migrations()

plugins/knowledgebase/migrations/script.py.mako

@@ -0,0 +1,24 @@
+"""${message}
+
+Revision ID: ${up_revision}
+Revises: ${down_revision | comma,n}
+Create Date: ${create_date}
+
+"""
+from alembic import op
+import sqlalchemy as sa
+${imports if imports else ""}
+
+# revision identifiers, used by Alembic.
+revision = ${repr(up_revision)}
+down_revision = ${repr(down_revision)}
+branch_labels = ${repr(branch_labels)}
+depends_on = ${repr(depends_on)}
+
+
+def upgrade():
+    ${upgrades if upgrades else "pass"}
+
+
+def downgrade():
+    ${downgrades if downgrades else "pass"}

plugins/knowledgebase/migrations/versions/0001_knowledgebase_anchor.py

@@ -0,0 +1,28 @@
+"""knowledgebase plugin anchor (ownership cutover).
+
+Stamp-only no-op. The core Alembic chain (baseline .. 7d16_directoryemployees)
+already created every table this plugin owns at the cutover point, so there is
+nothing to build here. This revision gives the plugin's own chain a base that
+`flask plugin upgrade-all` can stamp into alembic_version_knowledgebase. From this
+anchor forward, new knowledgebase schema changes land as 000N revisions in this
+directory, never in the core chain. See ADR-008.
+"""
+from alembic import op  # noqa: F401
+import sqlalchemy as sa  # noqa: F401
+
+
+# revision identifiers, used by Alembic.
+revision = 'knowledgebase0001anchor'
+down_revision = None
+branch_labels = None
+depends_on = None
+
+
+def upgrade():
+    # No-op: the core chain owns every table that exists at the cutover.
+    pass
+
+
+def downgrade():
+    # No-op: this anchor never unwinds core-owned tables.
+    pass