fix(permissions): param-aware DIS dead-allow + CNF conflict matching

The DIS scanner collapsed Tool(param) rules to the bare tool name, so
Agent(model:opus) deny + Agent(model:sonnet) allow (and the same for
WebFetch(domain:...)) were flagged as dead config — a false positive now
that CC 2.1.178 matches Tool(param:value) and 2.1.172 adds domain rules.
The conflict-detector shared the blind spot from the other side: a
wildcard deny like WebFetch(domain:*) did not cover a
WebFetch(domain:good.com) allow, so a genuine cross-scope conflict was
missed (false negative).

New shared scanners/lib/permission-rules.mjs:
- parseRule / paramMatches (glob)
- dominates(deny, allow) -> DIS dead-allow (deny fully covers allow)
- rulesIntersect(a, b)   -> CNF cross-scope conflict (match sets intersect)

DIS now delegates to dominates; conflict-detector :156 delegates to
rulesIntersect. A bare deny still covers all params, so true positives
are preserved (Bash deny + Bash(npm:*) allow still flagged).

Re-seeded the marketplace-medium snapshots: the false-positive CA-DIS
finding (Read(src/**) allow + Read(./.env) deny) is correctly gone. This
changes snapshot CONTENT only — envelope schema is unchanged, so --json
and --raw stay byte-stable.

Full suite: 837/837 green (+25). self-audit PASS, A(100)/A(97).

tests/snapshots/default-output/scan-orchestrator.json

@@ -517,29 +517,12 @@
         "status": "ok",
         "files_scanned": 1,
         "duration_ms": 0,
-        "findings": [
-          {
-            "id": "CA-DIS-001",
-            "scanner": "DIS",
-            "severity": "low",
-            "title": "A tool is in both the let-in list and the shut-out list",
-            "description": "When a tool is in both lists, the shut-out always wins, so the let-in entry does nothing. It looks like the tool is approved, but it isn't.",
-            "file": "/Users/ktg/repos/ktg-plugin-marketplace/config-audit/tests/fixtures/marketplace-medium/.claude/settings.json",
-            "line": null,
-            "evidence": "Read: allow=\"Read(src/**)\" + deny=\"Read(./.env)\"",
-            "category": "permissions-hygiene",
-            "recommendation": "Decide whether the tool should be allowed or denied, and remove it from the other list.",
-            "autoFixable": false,
-            "userImpactCategory": "Dead config",
-            "userActionLanguage": "Optional cleanup",
-            "relevanceContext": "test-fixture-no-impact"
-          }
-        ],
+        "findings": [],
         "counts": {
           "critical": 0,
           "high": 0,
           "medium": 0,
-          "low": 1,
+          "low": 0,
           "info": 0
         }
       },
@@ -559,15 +542,15 @@
       }
     ],
     "aggregate": {
-      "total_findings": 20,
+      "total_findings": 19,
       "counts": {
         "critical": 0,
         "high": 0,
         "medium": 1,
-        "low": 8,
+        "low": 7,
         "info": 11
       },
-      "risk_score": 12,
+      "risk_score": 11,
       "risk_band": "Medium",
       "verdict": "PASS",
       "scanners_ok": 11,