G0: cell substrate — invariants made executable

Strand G0 complete and VERIFIED against real Postgres, not asserted.

  - FastAPI plane, fail-closed provider seams, repair-pointer error taxonomy
  - migration 001: all 10 tables incl. repo_type NOT NULL and model_cards (I-7)
  - 17 invariant tests, ruff clean, vocabulary audit clean

Two bugs found by RUNNING it that review would not have caught:

  1. SQLAlchemy Enum persists .name, not .value — so RepoState.deleted_soft
     and CreatedVia.imported would have written labels migration 001 never
     declared, failing at runtime rather than at review. Pinned via
     values_callable.
  2. op.create_table asks each Enum to emit its own CREATE TYPE with no
     checkfirst, so the second reference raised DuplicateObject and the
     migration died halfway. Types are now created once, referenced with
     create_type=False.

Proven live, with the hostile env var set:
  - I-12: COMMIT_SHA=deadbeef... in the environment, /version reports real HEAD.
    That env pin is the documented root cause of nine sibling services
    misreporting their commit; here it is structurally ignored.
  - I-8: three unconfigured providers -> status degraded, HTTP 503, each saying
    'refusing to report healthy'. No mock, no false green.
  - G0.4: upgrade -> downgrade -> upgrade round-trip clean (10 -> 0 -> 10).

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

scripts/vocab_audit.py

@@ -0,0 +1,90 @@
+#!/usr/bin/env python3
+"""D-9 vocabulary audit (codon G12.6).
+
+"Git" is never a countable noun. There is no such thing as "a Git". Git is the
+program; a moment in time is a *commit*; user-facing it is a *version* or a
+*save point*; the container is a *repo*.
+
+This is not pedantry. It is the tell that separates people who use git from
+people who have read about it, and it will cost credibility with exactly the
+developer audience this product is built for. There is a second edge: *git* is
+British slang for a contemptible person -- which is why Torvalds chose it, self
+-deprecatingly -- so "tracking your Gits" reads badly to a Commonwealth ear.
+
+Doctrine files are exempt because they QUOTE the forbidden forms in order to
+forbid them. Any other file may exempt a single line with a `vocab-ok` marker.
+"""
+
+from __future__ import annotations
+
+import re
+import sys
+from pathlib import Path
+
+ROOT = Path(__file__).resolve().parents[1]
+
+# These files define the law and must quote what they prohibit.
+EXEMPT_FILES = {
+    "DNA_STRAND_MASTER_PLAN.md",
+    "README.md",
+    "AGENTS.md",
+    "scripts/vocab_audit.py",
+    "api/tests/test_d09_vocabulary.py",
+}
+
+SKIP_DIRS = {".git", ".venv", "venv", "__pycache__", ".ruff_cache", ".mypy_cache",
+             ".pytest_cache", "node_modules", "LICENSES", "patches"}
+
+SCAN_SUFFIXES = {".py", ".md", ".html", ".js", ".ts", ".jsx", ".tsx", ".json",
+                 ".yaml", ".yml", ".toml", ".txt", ".ini"}
+
+# "a Git" / "an Git" / "the Git" as a countable thing, plus the plural.
+# Negative lookahead keeps GitHub, Gitea, GitLab, Gitpod and "Git " as a proper
+# noun in phrases like "Windy Git is".
+PATTERNS = [
+    (re.compile(r"\b(?:a|an|one|each|every|another)\s+Git\b(?!Hub|ea|Lab|pod|Kraken)"),
+     'countable "a Git"'),
+    (re.compile(r"\bGits\b(?!Hub|ea)"), 'plural "Gits"'),
+    (re.compile(r"\b(?:my|your|their|his|her|its)\s+Git\b(?!Hub|ea|Lab|pod)"),
+     'possessive "your Git"'),
+    (re.compile(r"\bgits\b"), 'lowercase plural "gits"'),
+]
+
+
+def violations() -> list[tuple[str, int, str, str]]:
+    found: list[tuple[str, int, str, str]] = []
+    for path in ROOT.rglob("*"):
+        if not path.is_file() or path.suffix not in SCAN_SUFFIXES:
+            continue
+        if any(part in SKIP_DIRS for part in path.parts):
+            continue
+        rel = path.relative_to(ROOT).as_posix()
+        if rel in EXEMPT_FILES:
+            continue
+        try:
+            text = path.read_text(encoding="utf-8")
+        except (UnicodeDecodeError, OSError):
+            continue
+        for lineno, line in enumerate(text.splitlines(), 1):
+            if "vocab-ok" in line:
+                continue
+            for pattern, label in PATTERNS:
+                if pattern.search(line):
+                    found.append((rel, lineno, label, line.strip()[:100]))
+    return found
+
+
+def main() -> int:
+    found = violations()
+    if not found:
+        print("vocab audit: clean (D-9)")
+        return 0
+    print("D-9 VOCABULARY LAW VIOLATION -- 'Git' is not a countable noun.\n")
+    for rel, lineno, label, line in found:
+        print(f"  {rel}:{lineno}  {label}\n      {line}")
+    print("\nSay 'a commit' (developers) or 'a version' / 'a save point' (everyone else).")
+    return 1
+
+
+if __name__ == "__main__":
+    sys.exit(main())