fix(shared-infra): guard manifest.record_existing against non-file dst

Address Copilot review feedback on PR #2483. The previous fix called
``manifest.record_existing(rel_skip)`` from the skip branch of both
loops in ``install_shared_infra``, which would crash with
``IsADirectoryError`` (or another ``OSError``) if a directory or other
non-regular-file happened to exist at the expected destination path —
since ``record_existing`` opens the file to compute its SHA-256.

Three coordinated fixes:

1. ``IntegrationManifest.record_existing`` now validates its
   precondition: it raises ``ValueError`` if the path is a symlink or
   is not a regular file. The docstring already promised "an
   already-existing file"; this enforces it. The symlink check runs on
   the un-resolved path because ``_validate_rel_path`` calls
   ``resolve()``, which would silently follow the symlink. Mirrors the
   existing ``_ensure_safe_manifest_destination`` precedent in the
   same module.

2. In ``install_shared_infra``'s scripts and templates skip branches,
   guard the ``record_existing`` call with ``dst.is_file()`` and wrap
   it in ``try/except (OSError, ValueError)``. A directory collision,
   permission error, or TOCTOU race no longer aborts the whole
   install — the user gets a per-path warning, the path still
   surfaces in ``skipped_files``, and the rest of the install
   continues.

3. ``_read_manifest_files`` in the regression test no longer falls
   back to ``data.get("_files")`` (Copilot's low-confidence finding):
   the silent fallback could mask a schema regression where the
   public ``files`` key is renamed. It now asserts ``"files" in data``
   and that the value is a dict.

Add two regression tests in ``TestSpeckitManifestRecordsSkippedFiles``
covering the directory-at-destination edge case for both the scripts
loop and the templates loop. Both verify (a) install does not crash,
(b) the non-file path is not recorded in the manifest, and (c) the
path still surfaces in the user-visible warning.

The "shared infrastructure file(s)" warning text is changed to
"path(s)" so it remains accurate when non-file entries appear in the
list.

Refs #2107

src/specify_cli/integrations/manifest.py

@@ -147,12 +147,28 @@ class IntegrationManifest:
         return abs_path
 
     def record_existing(self, rel_path: str | Path) -> None:
-        """Record the hash of an already-existing file at *rel_path*.
+        """Record the hash of an already-existing regular file at *rel_path*.
 
-        Raises ``ValueError`` if *rel_path* resolves outside the project root.
+        Raises:
+            ValueError: if *rel_path* resolves outside the project root, is
+                a symlink, or is not a regular file. A directory or other
+                non-file path cannot be silently recorded — its hash would
+                be meaningless and ``check_modified``/``uninstall`` would
+                treat the entry as permanently broken.
         """
         rel = Path(rel_path)
+        # Check ``is_symlink()`` on the un-resolved path because
+        # ``_validate_rel_path`` resolves the path (which would follow
+        # the symlink and silently record the target instead).
+        if (self.project_root / rel).is_symlink():
+            raise ValueError(
+                f"Refusing to record symlinked manifest path: {rel}"
+            )
         abs_path = _validate_rel_path(rel, self.project_root)
+        if not abs_path.is_file():
+            raise ValueError(
+                f"Manifest path is not a regular file: {rel}"
+            )
         normalized = abs_path.relative_to(self.project_root).as_posix()
         self._files[normalized] = _sha256(abs_path)
 

src/specify_cli/shared_infra.py

@@ -435,7 +435,7 @@ def install_shared_infra(
 
     if skipped_files:
         console.print(
-            f"[yellow]⚠[/yellow]  {len(skipped_files)} shared infrastructure file(s) already exist and were not updated:"
+            f"[yellow]⚠[/yellow]  {len(skipped_files)} shared infrastructure path(s) already exist and were not updated:"
         )
         for path in skipped_files:
             console.print(f"    {path}")

tests/integrations/test_integration_claude.py

@@ -590,7 +590,21 @@ class TestSpeckitManifestRecordsSkippedFiles:
             f"speckit.manifest.json not written at {manifest_path}"
         )
         data = json.loads(manifest_path.read_text(encoding="utf-8"))
-        return data.get("files") or data.get("_files") or {}
+        # ``IntegrationManifest.save`` serialises a ``files`` dict — assert
+        # the schema explicitly so a regression to a different key (e.g.
+        # the internal ``_files`` attribute name) fails loudly instead of
+        # being masked by a silent fallback.
+        assert isinstance(data, dict), (
+            f"manifest root is not a dict, got {type(data).__name__}"
+        )
+        assert "files" in data, (
+            f"manifest missing 'files' key, got keys: {sorted(data.keys())}"
+        )
+        files = data["files"]
+        assert isinstance(files, dict), (
+            f"manifest 'files' is not a dict, got {type(files).__name__}"
+        )
+        return files
 
     def test_install_shared_infra_records_skipped_files(self, tmp_path):
         """With ``force=False`` and ``.specify/`` already populated, the
@@ -650,3 +664,97 @@ class TestSpeckitManifestRecordsSkippedFiles:
             f"these files were tracked on the first install but missing after "
             f"the skipped-files re-install: {sorted(missing)[:5]}"
         )
+
+    def test_install_shared_infra_handles_directory_at_script_destination(
+        self, tmp_path
+    ):
+        """A non-file (directory) at a script's destination must NOT crash
+        ``install_shared_infra`` and must NOT be recorded in the manifest —
+        the path still appears in the user-visible skipped-paths warning.
+        """
+        from io import StringIO
+        from rich.console import Console
+        from specify_cli.shared_infra import install_shared_infra
+
+        repo_root = Path(__file__).resolve().parents[2]
+        output = StringIO()
+        console = Console(file=output, force_terminal=False, width=200)
+
+        # Pre-create the .specify/scripts/bash tree, then plant a directory
+        # where a script file is expected so the skip branch hits a
+        # non-regular-file path.
+        bash_dir = tmp_path / ".specify" / "scripts" / "bash"
+        bash_dir.mkdir(parents=True)
+        (bash_dir / "common.sh").mkdir()  # collision: dir where file expected
+
+        # Must not crash.
+        install_shared_infra(
+            tmp_path,
+            "sh",
+            version="0.0.0",
+            core_pack=None,
+            repo_root=repo_root,
+            console=console,
+            force=False,
+        )
+
+        files = self._read_manifest_files(tmp_path)
+        assert ".specify/scripts/bash/common.sh" not in files, (
+            "directory at script dst must not be recorded in the manifest"
+        )
+        text = output.getvalue()
+        assert "common.sh" in text, (
+            "directory-at-script-dst path must surface in the skipped warning"
+        )
+
+    def test_install_shared_infra_handles_directory_at_template_destination(
+        self, tmp_path
+    ):
+        """Symmetric coverage for the templates loop: a directory at a
+        template's destination must NOT crash install nor be recorded."""
+        from io import StringIO
+        from rich.console import Console
+        from specify_cli.shared_infra import install_shared_infra
+
+        repo_root = Path(__file__).resolve().parents[2]
+        output = StringIO()
+        console = Console(file=output, force_terminal=False, width=200)
+
+        templates_dir = tmp_path / ".specify" / "templates"
+        templates_dir.mkdir(parents=True)
+
+        src_templates = repo_root / "templates"
+        real_template = next(
+            (
+                p.name
+                for p in src_templates.iterdir()
+                if p.is_file()
+                and not p.name.startswith(".")
+                and p.name != "vscode-settings.json"
+            ),
+            None,
+        )
+        assert real_template, (
+            "no real template found in repo to collide against"
+        )
+        (templates_dir / real_template).mkdir()  # collision
+
+        install_shared_infra(
+            tmp_path,
+            "sh",
+            version="0.0.0",
+            core_pack=None,
+            repo_root=repo_root,
+            console=console,
+            force=False,
+        )
+
+        files = self._read_manifest_files(tmp_path)
+        template_rel = f".specify/templates/{real_template}"
+        assert template_rel not in files, (
+            "directory at template dst must not be recorded in manifest"
+        )
+        text = output.getvalue()
+        assert real_template in text, (
+            "directory-at-template-dst path must surface in the skipped warning"
+        )