fix: remove non-spec trigger: field from skill frontmatter (#1180)

The Agent Skills spec only defines name, description, license,
compatibility, metadata, and allowed-tools as valid frontmatter fields.
The trigger: /graphify line was non-spec, silently ignored by spec-
following hosts, and flagged by agentskills validate CI checks.

- gen.py: removed trigger emission from _render_frontmatter; added
  _is_trigger_line() helper for roundtrip allow-list
- fragments/core/aider.md: removed hardcoded trigger: /graphify
- platforms.toml: removed trigger doc comment and trigger="" entries
- test_skillgen.py: replaced trigger-assertion tests with a single
  test asserting no host has trigger: in frontmatter
- Regenerated all 125 skill artifacts

Routing intent is preserved: the description field already contains
"treated as a graphify query first" and "graphify-out/ exists".

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

tests/test_skillgen.py

@@ -365,20 +365,13 @@ def test_all_progressive_hosts_check_and_audit_clean():
         assert probs == [], f"[{key}] audit\n" + "\n".join(probs)
 
 
-def test_kiro_and_pi_omit_the_trigger_line():
-    """kiro and pi render no frontmatter trigger (trigger absent in v8)."""
-    for key in ("kiro", "pi"):
+def test_no_host_has_trigger_in_frontmatter():
+    """No split host emits a trigger: field — not part of Agent Skills spec (#1180)."""
+    for key in ("claude", "codex", "opencode", "kilo", "copilot", "claw", "droid",
+                "amp", "trae", "vscode", "kiro", "pi"):
         core, _ = _platform_artifacts(key)
         head = core.split("---", 2)[1]
-        assert "trigger:" not in head, f"[{key}] unexpectedly has a trigger line"
-
-
-def test_triggered_hosts_keep_the_trigger_line():
-    """The other split hosts keep trigger: /graphify in the frontmatter."""
-    for key in ("opencode", "kilo", "copilot", "claw", "droid", "amp", "trae", "vscode"):
-        core, _ = _platform_artifacts(key)
-        head = core.split("---", 2)[1]
-        assert "trigger: /graphify" in head, f"[{key}] missing trigger line"
+        assert "trigger:" not in head, f"[{key}] unexpectedly has a trigger: line"
 
 
 def test_kilo_renders_its_rules_tail_section():
@@ -466,10 +459,15 @@ def test_monoliths_change_only_the_enum_description_and_chunk_cleanup():
     platforms = gen.load_platforms()
     for key in ("aider", "devin"):
         rendered = gen.render(platforms[key])[0].content.splitlines()
-        original = gen._normalise(gen._git_show(platforms[key].roundtrip_ref)).splitlines()
+        # Strip trigger: lines from the reference — their removal (#1180) is a
+        # permitted diff alongside enum, description, and chunk-cleanup changes.
+        original = [
+            l for l in gen._normalise(gen._git_show(platforms[key].roundtrip_ref)).splitlines()
+            if not gen._is_trigger_line(l)
+        ]
         assert len(rendered) == len(original), f"[{key}] line count changed"
         diff_idx = [i for i, (r, o) in enumerate(zip(rendered, original)) if r != o]
-        # Exactly four lines change: the prose enum guidance, the schema line,
+        # Four lines change: the prose enum guidance, the schema line,
         # the frontmatter description, and the chunk-cleanup rewrite.
         assert len(diff_idx) == 4, f"[{key}] expected 4 changed lines, got {len(diff_idx)}"
         enum_changes = 0