feat(mcp-docugen): templates seed versionati + auto-seed all'avvio

- templates_seed/{offerta,report-analisi}/template.md: template Tielogic
  ufficiali versionati come sorgente di verità nel repo
- template_seed.py: copia idempotente seed→volume al boot, mai
  sovrascrive template esistenti (preserva edit fatti via MCP runtime)
- config.py: nuova Settings.templates_seed_dir
  (default /app/services/mcp-docugen/templates_seed)
- main.py: chiamata seed_templates() in build_app dopo TemplateStore init
- 4 nuovi test unit (idempotenza, skip se seed_dir mancante,
  no-op su entry non valide). 72 test verde totali

Workflow: edit del template nel repo → rebuild image → al primo boot
il volume vuoto riceve i template; se il template esiste già nel
volume (es. modificato dall'utente via tool MCP) viene preservato.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

services/mcp-docugen/tests/unit/test_template_seed.py

@@ -0,0 +1,78 @@
+from __future__ import annotations
+
+from pathlib import Path
+
+from mcp_docugen.template_seed import seed_templates
+
+VALID_FRONTMATTER = (
+    "---\n"
+    "name: {name}\n"
+    "description: test seed\n"
+    "required_variables: []\n"
+    "---\n"
+    "body of {name}\n"
+)
+
+
+def _make_seed_template(seed_dir: Path, name: str, body: str | None = None) -> None:
+    tdir = seed_dir / name
+    (tdir / "assets").mkdir(parents=True, exist_ok=True)
+    (tdir / "template.md").write_text(
+        body if body is not None else VALID_FRONTMATTER.format(name=name)
+    )
+
+
+def test_seed_copies_missing_templates(tmp_path: Path) -> None:
+    seed_dir = tmp_path / "seed"
+    target_dir = tmp_path / "target"
+    _make_seed_template(seed_dir, "alpha")
+    _make_seed_template(seed_dir, "beta")
+
+    seeded = seed_templates(seed_dir, target_dir)
+
+    assert sorted(seeded) == ["alpha", "beta"]
+    assert (target_dir / "alpha" / "template.md").is_file()
+    assert (target_dir / "beta" / "template.md").is_file()
+    assert (target_dir / "alpha" / "assets").is_dir()
+
+
+def test_seed_is_idempotent_and_does_not_overwrite(tmp_path: Path) -> None:
+    seed_dir = tmp_path / "seed"
+    target_dir = tmp_path / "target"
+    _make_seed_template(seed_dir, "alpha")
+
+    seed_templates(seed_dir, target_dir)
+
+    user_edit = (
+        "---\nname: alpha\ndescription: edited by user\nrequired_variables: []\n---\n"
+        "user content\n"
+    )
+    (target_dir / "alpha" / "template.md").write_text(user_edit)
+
+    seeded = seed_templates(seed_dir, target_dir)
+
+    assert seeded == []
+    assert (target_dir / "alpha" / "template.md").read_text() == user_edit
+
+
+def test_seed_skips_when_seed_dir_missing(tmp_path: Path) -> None:
+    target_dir = tmp_path / "target"
+
+    seeded = seed_templates(tmp_path / "missing", target_dir)
+
+    assert seeded == []
+    assert not target_dir.exists() or list(target_dir.iterdir()) == []
+
+
+def test_seed_ignores_non_directory_entries_and_dirs_without_template(
+    tmp_path: Path,
+) -> None:
+    seed_dir = tmp_path / "seed"
+    target_dir = tmp_path / "target"
+    seed_dir.mkdir()
+    (seed_dir / "stray-file.md").write_text("not a template dir")
+    (seed_dir / "no-template-md").mkdir()
+
+    seeded = seed_templates(seed_dir, target_dir)
+
+    assert seeded == []