fix: resolve GitHub release asset API URL for private repo preset and workflow downloads (#2855)

* fix: resolve GitHub release asset API URL for private repo preset and workflow downloads

- Add shared `resolve_github_release_asset_api_url` utility to `_github_http.py` for
  reuse across preset and workflow download paths
- Apply the same private-repo fix from PR #2792 (extensions) to:
  - `PresetCatalog.download_pack` — ZIP downloads via catalog `download_url`
  - `preset add --from <url>` — ZIP downloads from a direct URL
  - `workflow add <url>` — workflow YAML downloads from a direct URL
  - `workflow add <id>` (catalog) — workflow YAML downloads via catalog `url`
- For browser release URLs (`github.com/…/releases/download/…`), the asset is
  resolved via the GitHub REST API and downloaded with `Accept: application/octet-stream`
- Direct REST API asset URLs (`api.github.com/…/releases/assets/<id>`) are
  downloaded directly with `Accept: application/octet-stream`
- Auth is preserved end-to-end through the existing `open_url` infrastructure
- Update `test_download_pack_sends_auth_header` and add
  `test_download_pack_accepts_direct_github_rest_asset_url` to cover both paths

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

* fix: URL-encode tag in release API URL to handle special characters

Encode the tag as a path segment (using quote with safe='') when
building the releases/tags/<tag> API URL. This prevents malformed
URLs when tags contain reserved characters like '/' or '#'.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* test: add CLI-level tests for preset add --from GitHub release URL resolution

Adds regression tests covering:
- resolve_github_release_asset_api_url unit tests (passthrough, resolution,
  network error, URL encoding of special chars in tags)
- CLI-level 'preset add --from <github-release-url>' end-to-end flow
- CLI-level 'preset add --from <api-asset-url>' direct passthrough

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* refactor: deduplicate release URL resolution; fix test issues

- ExtensionCatalog._resolve_github_release_asset_api_url now delegates
  to the shared helper in _github_http.py (also gains URL-encoding fix)
- Remove unused 'io' import from test_github_http.py
- Remove duplicate 'provides' dict keys accidentally added to test_presets.py

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* fix: align resolver timeout with download timeout; add workflow CLI tests

- Pass timeout=30 to resolve_github_release_asset_api_url in both
  workflow add paths so worst-case latency matches the download timeout
- Add CLI-level regression tests for 'workflow add <url>' covering
  browser URL resolution and direct API asset URL passthrough

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* fix: remove unused urllib.request import; add catalog workflow test

- Remove unused 'import urllib.request' in preset add --from path
- Add CLI test for catalog-based 'workflow add <id>' with GitHub
  release URL resolution

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* style: remove unused MagicMock imports from tests

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

---------

Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>
Co-authored-by: Manfred Riem <mnriem@users.noreply.github.com>
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

src/specify_cli/presets.py

@@ -1868,13 +1868,29 @@ class PresetCatalog:
         from specify_cli.authentication.http import build_request
         return build_request(url)
 
-    def _open_url(self, url: str, timeout: int = 10):
+    def _open_url(
+        self,
+        url: str,
+        timeout: int = 10,
+        extra_headers: Optional[Dict[str, str]] = None,
+    ):
         """Open a URL with provider-based auth, trying each configured provider.
 
         Delegates to :func:`specify_cli.authentication.http.open_url`.
         """
         from specify_cli.authentication.http import open_url
-        return open_url(url, timeout)
+        return open_url(url, timeout, extra_headers=extra_headers)
+
+    def _resolve_github_release_asset_api_url(
+        self,
+        download_url: str,
+        timeout: int = 60,
+    ) -> Optional[str]:
+        """Resolve a GitHub release asset URL to its REST API asset URL."""
+        from specify_cli._github_http import resolve_github_release_asset_api_url
+        return resolve_github_release_asset_api_url(
+            download_url, self._open_url, timeout=timeout
+        )
 
     def _load_catalog_config(self, config_path: Path) -> Optional[List[PresetCatalogEntry]]:
         """Load catalog stack configuration from a YAML file.
@@ -2332,8 +2348,14 @@ class PresetCatalog:
         zip_filename = f"{pack_id}-{version}.zip"
         zip_path = target_dir / zip_filename
 
+        extra_headers = None
+        resolved_download_url = self._resolve_github_release_asset_api_url(download_url)
+        if resolved_download_url:
+            download_url = resolved_download_url
+            extra_headers = {"Accept": "application/octet-stream"}
+
         try:
-            with self._open_url(download_url, timeout=60) as response:
+            with self._open_url(download_url, timeout=60, extra_headers=extra_headers) as response:
                 zip_data = response.read()
 
             zip_path.write_bytes(zip_data)