add pre-commit-secret-scan hook (blocks commits containing real credentials; install via core.hooksPath)

scripts/pre-commit-secret-scan.sh

@@ -0,0 +1,45 @@
+#!/bin/sh
+# pre-commit-secret-scan — blocks commits that would add real credentials.
+#
+# Deployed via core.hooksPath (e.g. ~/.config/git/hooks/pre-commit) so it runs
+# for EVERY repository on the machine. Fails OPEN (never blocks) if git itself
+# is unavailable. Override only when you're sure:  SKIP_SECRET_SCAN=1 git commit
+#
+# Pattern set covers the key formats used in this house: OpenAI sk-proj-,
+# OpenRouter sk-or-v1-, GitHub ghp_, Tavily tvly-, Gemini AIza*, ntfy-style
+# AQ.Ab*, JWTs (eyJ...), generic sk-... and Bearer tokens, private key blocks.
+# Lines that only REFERENCE keys (nix builtins.getEnv, literal '...'
+# placeholders) are ignored.
+
+[ -n "$SKIP_SECRET_SCAN" ] && exit 0
+
+# fail-open: not a git repo, or git unavailable
+git rev-parse --git-dir >/dev/null 2>&1 || exit 0
+
+# nothing staged -> nothing to check
+[ -n "$(git diff --cached --name-only 2>/dev/null)" ] || exit 0
+
+hits=$(git diff --cached -U0 --no-color 2>/dev/null | awk '
+  /^diff --git/ { f=$3; sub(/^a\//,"",f) }
+  /^\+/ && $0 !~ /^\+\+\+/ {
+    l = substr($0, 2)
+    if (l ~ /getEnv|\.\.\./) next
+    if (l ~ /sk-proj-[A-Za-z0-9._-]{20,}|sk-or-v1-[A-Za-z0-9._-]{20,}|ghp_[A-Za-z0-9]{20,}|tvly-[A-Za-z0-9]{20,}|AIza[A-Za-z0-9_-]{30,}|AQ\.Ab[A-Za-z0-9._-]{20,}|eyJ[A-Za-z0-9._-]{30,}|sk-[A-Za-z0-9]{25,}|Bearer [A-Za-z0-9._-]{25,}|BEGIN [A-Z ]*PRIVATE KEY/)
+      print f ": " l
+  }')
+
+[ -z "$hits" ] && exit 0
+
+echo "⛔ pre-commit secret scan BLOCKED — possible credentials in staged changes:" >&2
+echo "$hits" | sed -E '
+  s/(sk-proj-[A-Za-z0-9._-]{6})[A-Za-z0-9._-]+/\1…/g
+  s/(sk-or-v1-[A-Za-z0-9._-]{6})[A-Za-z0-9._-]+/\1…/g
+  s/(ghp_[A-Za-z0-9]{4})[A-Za-z0-9]+/\1…/g
+  s/(tvly-[A-Za-z0-9]{4})[A-Za-z0-9]+/\1…/g
+  s/(AIza[A-Za-z0-9_-]{4})[A-Za-z0-9_-]+/\1…/g
+  s/(AQ\.Ab[A-Za-z0-9._-]{4})[A-Za-z0-9._-]+/\1…/g
+  s/(eyJ[A-Za-z0-9._-]{8})[A-Za-z0-9._-]+/\1…/g
+  s/(sk-[A-Za-z0-9]{6})[A-Za-z0-9]+/\1…/g
+  s/(Bearer [A-Za-z0-9._-]{6})[A-Za-z0-9._-]+/\1…/g' >&2
+echo "→ Remove the secret and re-commit. If it's a false positive: SKIP_SECRET_SCAN=1 git commit" >&2
+exit 1