feat: Archivum skeleton — Go/GraphQL backend + Vue 3 PWA frontend

Full project scaffold: multi-stage Dockerfile (ARM64/AMD64), AsciiDoc↔TipTap
bridge, Setup Wizard, CodeMirror source editor, Git-backed storage layer,
LDAP+JWT auth skeleton, Tailwind mobile-first layout, and VS Code build/push
tasks targeting registry at 192.168.0.19:5000.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

backend/internal/graph/schema.graphql

@@ -0,0 +1,87 @@
+type Query {
+  # Returns REQUIRE_SETUP if config is missing.
+  systemStatus: SystemStatus!
+
+  # Fetch a document by its slug path.
+  document(slug: String!): Document
+
+  # List documents under an optional path prefix.
+  documents(prefix: String): [DocumentMeta!]!
+
+  # Commit history for a document.
+  history(slug: String!): [CommitEntry!]!
+
+  # Unified diff between two commits for a document.
+  diff(slug: String!, fromHash: String!, toHash: String!): String!
+
+  # Raw content of a document at a specific commit.
+  documentAtCommit(slug: String!, hash: String!): String!
+}
+
+type Mutation {
+  # First-run setup.
+  setup(input: SetupInput!): Boolean!
+
+  # Authenticate and receive a bearer token.
+  login(username: String!, password: String!): String!
+
+  # Invalidate the current session.
+  logout: Boolean!
+
+  # Save (create or update) a document.
+  saveDocument(input: SaveDocumentInput!): Document!
+
+  # Delete a document.
+  deleteDocument(slug: String!): Boolean!
+}
+
+# ── Types ──────────────────────────────────────────────────────────────────────
+
+enum SystemStatus {
+  OK
+  REQUIRE_SETUP
+}
+
+type Document {
+  slug:    String!
+  content: String!
+  meta:    DocumentMeta!
+}
+
+type DocumentMeta {
+  slug:      String!
+  title:     String!
+  updatedAt: String!
+}
+
+type CommitEntry {
+  hash:    String!
+  author:  String!
+  email:   String!
+  date:    String!
+  subject: String!
+}
+
+# ── Inputs ─────────────────────────────────────────────────────────────────────
+
+input SetupInput {
+  storagePath: String!
+  adminUser:   String!
+  adminPass:   String!
+  ldap:        LDAPInput
+  jwtSecret:   String!
+}
+
+input LDAPInput {
+  host:         String!
+  port:         Int!
+  baseDN:       String!
+  bindDN:       String!
+  bindPassword: String!
+}
+
+input SaveDocumentInput {
+  slug:          String!
+  content:       String!
+  commitMessage: String!
+}