fix(skills): pull full ClawHub catalog into the skills index (200 → 20k+) (#33748)

* fix(skills): pull full ClawHub catalog into the skills index

The website was showing 200 ClawHub skills out of 20k+ because
`ClawHubSource.search("")` for empty queries went straight to a single
unpaginated request. ClawHub's API caps any single page at 200 items and
returns a `nextCursor`; we grabbed page 1 and stopped, so the cached
index served from hermes-agent.nousresearch.com had a silent 99%
truncation.

End users never hit clawhub.ai directly (the index is rebuilt twice
daily by .github/workflows/skills-index.yml and served as a static JSON
on the docs site), so the cap-and-cache architecture is correct — it
just wasn't being filled.

Changes:
- `ClawHubSource.search(query="")` now routes through the existing
  `_load_catalog_index()` paginating walker instead of the unpaginated
  listing fallback (non-empty queries still hit the fast catalog search).
- `_load_catalog_index()` max_pages 50 → 250 (50k-skill ceiling; live
  catalog is ~20k as of May 2026, with headroom for growth).
- `build_skills_index.py`: per-source crawl limits split out — ClawHub
  and LobeHub get 100k, others keep their effective caps.
- `EXPECTED_FLOORS["clawhub"]` 50 → 5000 so the next pagination
  regression hard-fails the CI build instead of silently shipping a
  degenerate index.

Test plan:
- New unit test `test_search_empty_query_paginates_full_catalog`
  exercises the cursor-following path with three mocked pages (450
  total items) and asserts all pages are walked.
- Existing 9 ClawHub tests + 127 broader skills_hub tests all pass.
- E2E against live ClawHub API: walker reached 9700+ skills across 49
  pages before this commit landed, paginating well past the previous
  50-page cap.

* fix(skills): raise ClawHub ceilings — live catalog is 50k, not 20k

E2E walk against live ClawHub API hit my initial 250-page cap at 49,698
skills with cursor=yes still pending. The catalog is roughly 2.5x larger
than the docstring estimate.

- max_pages 250 → 750 (150k ceiling, walks terminate on cursor=None
  well before this in practice)
- SOURCE_LIMITS['clawhub'] 100k → 200k
- EXPECTED_FLOORS['clawhub'] 5000 → 20000

scripts/build_skills_index.py

@@ -269,11 +269,28 @@ def main():
     # Crawl skills.sh
     all_skills.extend(crawl_skills_sh(skills_sh_source))
 
-    # Crawl other sources in parallel
+    # Crawl other sources in parallel.
+    # Per-source soft caps — sources stop returning when they run out, so these
+    # are ceilings, not targets.  ClawHub has 20k+ skills; bumping to 100k
+    # (well above current catalog size) lets the full catalog land in the
+    # index instead of being truncated at an arbitrary build-time limit.
+    SOURCE_LIMITS = {
+        # ClawHub had 49,698+ skills as of May 2026; 200k leaves headroom.
+        "clawhub": 200_000,
+        "lobehub": 100_000,
+        "browse-sh": 5_000,
+        "claude-marketplace": 5_000,
+        "github": 5_000,
+        "well-known": 5_000,
+        "official": 5_000,
+    }
+    DEFAULT_SOURCE_LIMIT = 500
+
     with ThreadPoolExecutor(max_workers=4) as pool:
         futures = {}
         for name, source in sources.items():
-            futures[pool.submit(crawl_source, source, name, 500)] = name
+            limit = SOURCE_LIMITS.get(name, DEFAULT_SOURCE_LIMIT)
+            futures[pool.submit(crawl_source, source, name, limit)] = name
         for future in as_completed(futures):
             try:
                 all_skills.extend(future.result())
@@ -330,7 +347,11 @@ def main():
     EXPECTED_FLOORS = {
         "skills.sh": 100,
         "lobehub": 100,
-        "clawhub": 50,
+        # ClawHub had 49,698+ skills as of May 2026 — anything under 20k means
+        # pagination broke or the API surface changed.  Fail loudly rather
+        # than ship a degenerate index (we shipped 200/50000 silently for
+        # weeks because the floor was 50).
+        "clawhub": 20000,
         "official": 50,
         "github": 30,        # collapsed across all GitHub taps
         "browse-sh": 50,