refactor: remove the claude-marketplace skill source (redundant Marketplace hub tab)

The Skills Hub 'Marketplace' tab showed a single useless entry: Anthropic
changed .claude-plugin/marketplace.json to bundle-shaped plugins whose
source is './', so all plugins collapsed to one identifier pointing at the
repo root, and the second marketplace repo (aiskillstore/marketplace) is
gone (404). Everything in anthropics/skills is already surfaced by the
GitHub tap as the Anthropic tab, making this source fully redundant.

Removes ClaudeMarketplaceSource and all wiring: source router, index
builder (crawl + floors + sort order + rate-limit messaging), extract
labels/install/URL mapping, hub UI tab, web server labels, CLI limits,
docs (en + zh), the legacy index-cache snapshot, and test fixtures.

Stale skills-index entries with source 'claude-marketplace' still install
fine: HermesIndexSource fetches via resolved GitHub paths generically.

website/scripts/extract-skills.py

@@ -10,7 +10,7 @@ Two data sources:
 2. The unified Hermes Skills Index at ``website/static/api/skills-index.json``,
    built twice daily by ``scripts/build_skills_index.py`` (workflow
    ``.github/workflows/skills-index.yml``). Covers skills.sh, ClawHub, browse.sh,
-   LobeHub, Claude Marketplace, well-known endpoints, and the GitHub taps
+   LobeHub, well-known endpoints, and the GitHub taps
    (openai/skills, anthropics/skills, huggingface/skills, VoltAgent, etc.).
 
 Legacy fallback: if the unified index is missing AND ``skills/index-cache/``
@@ -82,7 +82,6 @@ UNIFIED_SOURCE_LABELS = {
     "clawhub": "ClawHub",
     "browse-sh": "browse.sh",
     "lobehub": "LobeHub",
-    "claude-marketplace": "Claude Marketplace",
     "well-known": "Well-Known",
     "github": "GitHub",  # default for non-named GitHub taps
 }
@@ -106,7 +105,6 @@ GITHUB_TAP_LABELS = {
 LEGACY_SOURCE_LABELS = {
     "anthropics_skills": "Anthropic",
     "openai_skills": "OpenAI",
-    "claude_marketplace": "Claude Marketplace",
     "lobehub": "LobeHub",
 }
 
@@ -184,8 +182,6 @@ def _install_command(source: str, identifier: str, name: str) -> str:
         return f"hermes skills install {identifier}"
     if src == "lobehub":
         return f"hermes skills install {identifier}"
-    if src == "claude-marketplace":
-        return f"hermes skills install {identifier}"
     if src == "github":
         return f"hermes skills install {identifier}"
     if src == "well-known":
@@ -215,8 +211,7 @@ def _source_url(source: str, identifier: str, extra: dict) -> str:
     # GitHub-backed taps (openai/anthropic/nvidia/hf/gstack/VoltAgent/...):
     # identifier is "owner/repo/<path...>" — link to the directory on GitHub.
     if src in {"github", "openai", "anthropic", "huggingface", "nvidia",
-               "gstack", "voltagent", "minimax", "claude marketplace",
-               "claude-marketplace"}:
+               "gstack", "voltagent", "minimax"}:
         parts = [p for p in identifier.split("/") if p]
         if len(parts) >= 2:
             owner, repo = parts[0], parts[1]