feat: one generic image, with installed modules in installation-owned storage (ADR 0048)

The production image now contains zero feature modules and is the same for every
installation. Installed modules live in module storage that one Core resolver
selects from EKKLESIA_MODULES_DIR: the checkout's modules/ when unset, an
absolute path that must exist when set (/var/lib/ekklesia/modules in the image).
A relative, blank, missing, or unreadable configured directory fails closed with
a sanitized error that never contains the value.

- Host configuration reads EKKLESIA_MODULES_DIR. The API, migration plan, apply
  and validate, module validation, module enablement, and Doctor all resolve it
  the same way; the test-only API override still takes precedence.
- Doctor receives Core's migrations directory explicitly instead of deriving it
  from the modules directory's parent.
- The migration runner retains and reports the applied history of a module that
  is not installed, and plans and applies Core's and present modules' migrations
  around it. Core's history and every installed module's history stay strict: a
  missing or changed applied migration, or a downgrade, still fails. No down
  migrations, no data deletion.
- deploy/Dockerfile copies no module and installs nothing for the module
  template; .dockerignore excludes modules/ and the build refuses a context that
  contains it; the runtime has an empty root-owned /var/lib/ekklesia/modules and
  sets EKKLESIA_MODULES_DIR.
- deploy/compose.yaml bind-mounts EKKLESIA_MODULES_HOST_DIR read-only into api
  and migrate, with create_host_path disabled.
- scripts/check-image.sh proves the image holds no modules and that a populated
  modules/ directory leaves its runtime file system identical; CI runs it.
- The split deploy smoke now uses the same generic image: it boots with no
  modules, installs a self-contained test module packaged from the template
  (test-only), migrates and restarts, removes it (Core runs, planning reports the
  retained history, data survives), and restores it with its data.

Docs: deploy README (module storage, install/update/remove/restore, the runtime
modules target), .env.example, API configuration, module development guide,
testing, workflow, security, and the architecture overview.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

core/tests/doctor.test.ts

@@ -1,5 +1,9 @@
 import { type ModuleManifest, parsePermissionId } from "@ekklesia/contracts";
-import { describe, expect, it, vi } from "vitest";
+import { mkdtemp, rm } from "node:fs/promises";
+import { tmpdir } from "node:os";
+import path from "node:path";
+import { fileURLToPath } from "node:url";
+import { afterEach, describe, expect, it, vi } from "vitest";
 import { createPermissionRegistry, PermissionRegistryError } from "../src/authorization/index.js";
 import {
   type DoctorCheck,
@@ -114,7 +118,10 @@ function emptyDatabase(): MigrationDatabase {
   });
 }
 
-function plan(entries: MigrationPlanResult["entries"] = []): MigrationPlanResult {
+function plan(
+  entries: MigrationPlanResult["entries"] = [],
+  retained: MigrationPlanResult["retained"] = [],
+): MigrationPlanResult {
   const appliedCount = entries.filter((entry) => entry.status === "applied").length;
   const approvalRequiredCount = entries.filter(
     (entry) => entry.status === "approval-blocked",
@@ -124,6 +131,7 @@ function plan(entries: MigrationPlanResult["entries"] = []): MigrationPlanResult
     approvalRequiredCount,
     entries: Object.freeze([...entries]),
     pendingCount: entries.length - appliedCount,
+    retained: Object.freeze([...retained]),
   });
 }
 
@@ -151,6 +159,7 @@ function dependencies(overrides: Partial<DoctorDependencies> = {}): DoctorDepend
 function options(databaseUrl?: string): DoctorOptions {
   return {
     ...(databaseUrl === undefined ? {} : { databaseUrl }),
+    coreMigrationsDirectory: "/not-rendered/core/drizzle",
     moduleDiscovery: {
       moduleSdkVersion: "0.1.0",
       modulesDirectory: "/not-rendered/modules",
@@ -1657,3 +1666,113 @@ describe("Doctor reports declared browser contributions", () => {
     ]);
   });
 });
+
+describe("Doctor with installation-owned module storage (ADR 0048)", () => {
+  const platformCoreMigrations = path.join(
+    path.dirname(fileURLToPath(import.meta.url)),
+    "..",
+    "drizzle",
+  );
+  const temporaryDirectories: string[] = [];
+
+  afterEach(async () => {
+    await Promise.all(
+      temporaryDirectories.splice(0).map((directory) => rm(directory, { recursive: true })),
+    );
+  });
+
+  it("finds Core's migrations where the platform is installed, not beside the modules", async () => {
+    // A modules directory far from the platform, as the image mounts /var/lib/ekklesia/modules. Its
+    // parent has no `core/drizzle`, so a Doctor that still derived Core's migrations from the
+    // modules directory would fail migration discovery here.
+    const external = await mkdtemp(path.join(tmpdir(), "ekklesia-external-modules-"));
+    temporaryDirectories.push(external);
+    const report = await diagnoseEkklesia({
+      coreMigrationsDirectory: platformCoreMigrations,
+      moduleDiscovery: {
+        moduleSdkVersion: "0.1.0",
+        modulesDirectory: external,
+        modulesDirectoryRequired: true,
+        platformVersion: "0.1.0",
+      },
+      runtimeRange: ">=24.11.0 <25",
+      runtimeVersion: "24.15.0",
+    });
+
+    expect(check(report, "modules.discovery").status).toBe("pass");
+    const migrations = check(report, "migrations.discovery");
+    expect(migrations.status).toBe("pass");
+    expect(migrations.details.some((detail) => detail.startsWith("core:0000_"))).toBe(true);
+    expect(JSON.stringify(report)).not.toContain(external);
+  });
+
+  it("reports an unusable configured modules directory as a discovery failure, naming no path", async () => {
+    const report = await diagnoseEkklesia({
+      coreMigrationsDirectory: platformCoreMigrations,
+      moduleDiscovery: {
+        moduleSdkVersion: "0.1.0",
+        modulesDirectory: "relative/private-mount-3c9d",
+        modulesDirectoryRequired: true,
+        platformVersion: "0.1.0",
+      },
+      runtimeRange: ">=24.11.0 <25",
+      runtimeVersion: "24.15.0",
+    });
+
+    const discovery = check(report, "modules.discovery");
+    expect(discovery.status).toBe("failure");
+    expect(discovery.details).toEqual(["The configured modules directory is not usable."]);
+    expect(check(report, "migrations.discovery").status).toBe("skipped");
+    expect(JSON.stringify(report)).not.toContain("private-mount-3c9d");
+  });
+
+  it("reports a configured modules directory that does not exist, naming no path", async () => {
+    const parent = await mkdtemp(path.join(tmpdir(), "ekklesia-missing-modules-"));
+    temporaryDirectories.push(parent);
+    const report = await diagnoseEkklesia({
+      coreMigrationsDirectory: platformCoreMigrations,
+      moduleDiscovery: {
+        moduleSdkVersion: "0.1.0",
+        modulesDirectory: path.join(parent, "absent"),
+        modulesDirectoryRequired: true,
+        platformVersion: "0.1.0",
+      },
+      runtimeRange: ">=24.11.0 <25",
+      runtimeVersion: "24.15.0",
+    });
+
+    const discovery = check(report, "modules.discovery");
+    expect(discovery.status).toBe("failure");
+    expect(discovery.details).toEqual(["The configured modules directory could not be read."]);
+    expect(JSON.stringify(report)).not.toContain(parent);
+  });
+
+  it("reports an absent module's retained history without blocking readiness", async () => {
+    const report = await diagnoseEkklesia(
+      options("postgres://[email protected]/ekklesia"),
+      dependencies({
+        planMigrations: vi.fn(async () =>
+          plan(
+            [planEntry("core:0000_identity_core_tables", "a".repeat(64), "applied")],
+            [Object.freeze({ appliedCount: 2, moduleId: "calendar" })],
+          ),
+        ),
+      }),
+    );
+
+    const planCheck = check(report, "postgresql.plan");
+    expect(planCheck.status).toBe("pass");
+    expect(planCheck.details).toContain(
+      "retained · calendar · 2 applied migrations kept; the module is not installed",
+    );
+  });
+
+  it("passes Core's own migration directory to migration discovery", async () => {
+    const discoverMigrations = vi.fn(async () => migrationAggregate());
+    await diagnoseEkklesia(options(), dependencies({ discoverMigrations }));
+    expect(discoverMigrations).toHaveBeenCalledWith({
+      coreMigrationsDirectory: "/not-rendered/core/drizzle",
+      moduleDiscovery: options().moduleDiscovery,
+    });
+  });
+});