fix: use bounded read for integration catalog HTTP responses (#3763)

* fix(skills): match closing frontmatter delimiter on its own line

SkillsIntegration.setup parsed each command template's frontmatter with
raw.split("---", 2). A bare substring split stops at the first `---`
*anywhere*, so a template whose description embeds `---` (e.g.
"Separate sections with --- markers") truncated the parsed frontmatter:
later keys were dropped, the description fell back to the generic default,
and the leftover frontmatter spilled into the skill body.

Scan for the closing `---` on its own line instead, for both the
description parse and the body strip. The frontmatter block is parsed
unstripped so trailing newlines in literal (|) block scalars still survive,
and the body slice keeps the newline after the marker so output stays
byte-for-byte identical to the old split for well-formed templates.

Adds regression tests covering the dashed-description truncation and the
frontmatter-spilled-into-body cases.

* fix: use bounded read for integration catalog HTTP responses

The integration catalog fetch used unbounded resp.read() to read
HTTP responses into memory. A malicious or misconfigured catalog
server could return an arbitrarily large response causing OOM.

Replace with read_response_limited() capped at MAX_JSON_METADATA_BYTES
(1 MiB), consistent with how other JSON fetch paths in the codebase
(_version.py, _github_http.py, authentication/azure_devops.py) already
enforce bounded reads.

Pass error_type=IntegrationCatalogError so oversized catalogs are
caught by the existing per-entry recovery path in
_get_merged_integrations() rather than aborting the entire merge.

Add regression test verifying oversized responses are rejected as
IntegrationCatalogError and that healthy catalogs remain usable.

src/specify_cli/integrations/base.py

@@ -1652,13 +1652,27 @@ class SkillsIntegration(IntegrationBase):
             command_name = src_file.stem  # e.g. "plan"
             skill_name = f"speckit-{command_name.replace('.', '-')}"
 
-            # Parse frontmatter for description
+            # Parse frontmatter for description. Locate the closing ``---`` on
+            # its own line rather than with ``raw.split("---", 2)`` — a bare
+            # substring split stops at the first ``---`` *anywhere*, including
+            # one inside a value such as ``description: Separate sections
+            # with ---``, which truncates the frontmatter and drops later keys.
+            # The block between the delimiters is parsed unstripped so trailing
+            # newlines in literal (``|``) block scalars survive.
             frontmatter: dict[str, Any] = {}
             if raw.startswith("---"):
-                parts = raw.split("---", 2)
-                if len(parts) >= 3:
+                fm_lines = raw.splitlines(keepends=True)
+                fm_close = next(
+                    (
+                        i
+                        for i in range(1, len(fm_lines))
+                        if fm_lines[i].rstrip() == "---"
+                    ),
+                    None,
+                )
+                if fm_close is not None:
                     try:
-                        fm = yaml.safe_load(parts[1])
+                        fm = yaml.safe_load("".join(fm_lines[1:fm_close]))
                         if isinstance(fm, dict):
                             frontmatter = fm
                     except yaml.YAMLError:
@@ -1673,11 +1687,27 @@ class SkillsIntegration(IntegrationBase):
             # Strip the processed frontmatter — we rebuild it for skills.
             # Preserve leading whitespace in the body to match release ZIP
             # output byte-for-byte (the template body starts with \n after
-            # the closing ---).
+            # the closing ---). Scan for the closing ``---`` on its own line
+            # rather than ``split("---", 2)`` so a ``---`` embedded in a value
+            # does not truncate the frontmatter and spill it into the body.
             if processed_body.startswith("---"):
-                parts = processed_body.split("---", 2)
-                if len(parts) >= 3:
-                    processed_body = parts[2]
+                body_lines = processed_body.splitlines(keepends=True)
+                close_idx = next(
+                    (
+                        i
+                        for i in range(1, len(body_lines))
+                        if body_lines[i].rstrip() == "---"
+                    ),
+                    None,
+                )
+                if close_idx is not None:
+                    # Keep whatever trails the ``---`` marker on the closing
+                    # line (normally just the newline) so the body stays
+                    # byte-for-byte identical to ``split("---", 2)[2]``. The
+                    # line-anchored check guarantees ``---`` sits at index 0.
+                    processed_body = body_lines[close_idx][3:] + "".join(
+                        body_lines[close_idx + 1 :]
+                    )
 
             # Select description — use the original template description
             # to stay byte-for-byte identical with release ZIP output.