feat(software): catalog + customer assignments (M2M)

Software catalog with per-customer assignments via the customer_software
join table. Two tabs in one /software page:

Catalog tab:
- Software CRUD: name, version, description, defaultFee (TRY).
- Deleting a software cascades and removes all its assignments first
  (best-effort loop, then the catalog row), all wrapped in audit logs.

Assignments tab:
- M2M between customer and software with own fee (overrides defaultFee),
  billingPeriod (monthly default), startDate/endDate, notes.
- Form auto-fills fee from selected software's defaultFee.
- Both Sheet forms localized; date inputs round-tripped via toIsoDate
  (Appwrite expects ISO 8601 with TZ; HTML date input gives YYYY-MM-DD).
- Delete dialogs differentiated for catalog ('siliniyor') vs assignment
  ('kaldırılıyor').

New files:
- lib/validation/software.ts (softwareSchema + customerSoftwareSchema)
- lib/appwrite/software-actions.ts (6 server actions)
- lib/appwrite/software-queries.ts (listSoftware, listAssignments)
- lib/appwrite/software-types.ts (form state)
- /software route with SoftwareClient (Tabs), SoftwareFormSheet,
  AssignmentFormSheet, inline delete dialogs.

Empty states surface the right next-step CTA: 'önce müşteri ekleyin', or
'önce yazılım ekleyin', as appropriate.

src/lib/appwrite/software-queries.ts

@@ -0,0 +1,47 @@
+import "server-only";
+
+import { Query } from "node-appwrite";
+
+import { createAdminClient } from "./server";
+import {
+  DATABASE_ID,
+  TABLES,
+  type CustomerSoftware,
+  type Software,
+} from "./schema";
+
+export async function listSoftware(tenantId: string): Promise<Software[]> {
+  try {
+    const { tablesDB } = createAdminClient();
+    const result = await tablesDB.listRows({
+      databaseId: DATABASE_ID,
+      tableId: TABLES.software,
+      queries: [
+        Query.equal("tenantId", tenantId),
+        Query.orderAsc("name"),
+        Query.limit(500),
+      ],
+    });
+    return result.rows as unknown as Software[];
+  } catch {
+    return [];
+  }
+}
+
+export async function listAssignments(tenantId: string): Promise<CustomerSoftware[]> {
+  try {
+    const { tablesDB } = createAdminClient();
+    const result = await tablesDB.listRows({
+      databaseId: DATABASE_ID,
+      tableId: TABLES.customerSoftware,
+      queries: [
+        Query.equal("tenantId", tenantId),
+        Query.orderDesc("$createdAt"),
+        Query.limit(1000),
+      ],
+    });
+    return result.rows as unknown as CustomerSoftware[];
+  } catch {
+    return [];
+  }
+}