ci(release): hook + release guide cover the fallback header; checker nits

Review on #795:
- Copilot: the pre-commit hook ran check-info-version.sh only for
  dist/info/ or Makefile changes; version_fallback.h now triggers it too.
- Copilot: docs/release-process.md still said to bump only the Makefile
  and check only .info; both places now name all three copies.
- Kimi: missing-file check for all three inputs, set -eu, and the version
  parse stops at the first closing quote (a trailing comment on the
  #define no longer leaks into the value -- tested with a mismatch).

Co-Authored-By: Claude Opus 5.5 <[email protected]>

docs/release-process.md

@@ -16,7 +16,7 @@ PRs targeting `master` directly trigger a friendly comment from `.github/workflo
 
 ## TL;DR
 
-1. Cut `release/X.Y.Z` from `develop`.  Bump `CORE_BASE_VERSION` in `Makefile` (or use the `Bump Version & Release` workflow).  Update `docs/RELEASE_NOTES_vX.Y.Z.md`.  Open a PR from `release/X.Y.Z` → `master`.
+1. Cut `release/X.Y.Z` from `develop`.  Bump the version in all three places -- `CORE_BASE_VERSION` in `Makefile`, `display_version` in `dist/info/virtualjaguar_libretro.info`, and `CORE_BASE_VERSION` in `src/core/version_fallback.h` (or use the `Bump Version & Release` workflow); `scripts/check-info-version.sh` fails CI if they drift.  Update `docs/RELEASE_NOTES_vX.Y.Z.md`.  Open a PR from `release/X.Y.Z` → `master`.
 2. Merge into `master`.
 3. `git tag vX.Y.Z && git push libretro vX.Y.Z` (or via GitHub UI).
 4. Watch [Actions](https://github.com/libretro/virtualjaguar-libretro/actions) — `release.yml` builds 16 platforms (14 in the build matrix, plus Vita and Switch in their own jobs), generates `SHA256SUMS.txt`, and publishes the release with `docs/RELEASE_NOTES_vX.Y.Z.md` as the body.
@@ -41,6 +41,7 @@ PRs targeting `master` directly trigger a friendly comment from `.github/workflo
 - CI on the release PR is green except `claude-review` (non-blocking; AI review service refuses diffs > 20k lines).
 - `docs/WHATSNEW` v`X.Y.Z` section is up-to-date.
 - `docs/RELEASE_NOTES_vX.Y.Z.md` exists. (See below for how to generate one.)
+- `src/core/version_fallback.h` `CORE_BASE_VERSION` matches the new tag (`scripts/check-info-version.sh` checks all three copies).
 - `dist/info/virtualjaguar_libretro.info` is up-to-date — `display_version` matches the new tag, any new feature flags are reflected (`savestate`, `cheats`, `disk_control`, `hw_render`, etc.).
 
 ### 2. Tag

scripts/check-info-version.sh

@@ -6,22 +6,24 @@
 # ship with a stale .info field (RetroArch's "core version" UI) or a stale
 # fallback header (v3.6.1 nearly did, #734).
 
-set -e
+set -eu
 
 ROOT=$(cd "$(dirname "$0")/.." && pwd)
 INFO="$ROOT/dist/info/virtualjaguar_libretro.info"
 MAKEFILE="$ROOT/Makefile"
 FALLBACK="$ROOT/src/core/version_fallback.h"
 
-if [ ! -f "$INFO" ]; then
-  echo "::error::missing $INFO"
-  exit 1
-fi
+for f in "$MAKEFILE" "$INFO" "$FALLBACK"; do
+  if [ ! -f "$f" ]; then
+    echo "::error::missing $f"
+    exit 1
+  fi
+done
 
 # Portable across BSD/GNU sed.
 MAKE_VER=$(sed -n 's/^CORE_BASE_VERSION[[:space:]]*:*=[[:space:]]*\(.*\)/\1/p' "$MAKEFILE" | head -1)
-INFO_VER=$(sed -n 's/^display_version[[:space:]]*=[[:space:]]*"\(.*\)"/\1/p' "$INFO" | head -1)
-FALLBACK_VER=$(sed -n 's/^#define[[:space:]]*CORE_BASE_VERSION[[:space:]]*"\(.*\)"/\1/p' "$FALLBACK" | head -1)
+INFO_VER=$(sed -n 's/^display_version[[:space:]]*=[[:space:]]*"\([^"]*\)".*/\1/p' "$INFO" | head -1)
+FALLBACK_VER=$(sed -n 's/^#define[[:space:]]*CORE_BASE_VERSION[[:space:]]*"\([^"]*\)".*/\1/p' "$FALLBACK" | head -1)
 
 if [ -z "$MAKE_VER" ]; then
   echo "::error::could not parse CORE_BASE_VERSION from $MAKEFILE"

scripts/install-hooks.sh

@@ -27,8 +27,8 @@ if [ -n "$STAGED_C" ]; then
   scripts/c89-lint.sh $STAGED_C
 fi
 
-# .info / Makefile version sync check
-if echo "$STAGED" | grep -qE '^(dist/info/|Makefile$)'; then
+# Version sync check: Makefile, .info and the fallback header (#734)
+if echo "$STAGED" | grep -qE '^(dist/info/|Makefile$|src/core/version_fallback\.h$)'; then
   scripts/check-info-version.sh
 fi