subwave: add 4 more 1996 shows, add artist-score floor to fix false match

Adds Tunecaster Rock Top 30 for 1996-01-13, 1996-04-13, 1996-07-13, and
1996-12-14, cross-checked against all 4 existing 1995 shows and each other
for exact-track duplicates.

Also fixes a real false-positive: "John Mellencamp - Just Another Day" was
matching Jon Secada's unrelated song of the same generic title, because a
perfect title score could carry a middling-but-not-absurd artist-name
coincidence (0.56) over the acceptance threshold. Added a hard artist
similarity floor (0.65) independent of the combined score.

Claude-Session: https://claude.ai/code/session_01L7Rwa6guD5wK8F8tWQwcJX

subwave/broadcasts/tunecaster-rock-1996-01-13.json

@@ -0,0 +1,116 @@
+{
+  "station": "Tunecaster Rock Top 30",
+  "date": "1996-01-13",
+  "tracks": [
+    {
+      "rank": 3,
+      "artist": "Pearl Jam",
+      "title": "I Got ID"
+    },
+    {
+      "rank": 4,
+      "artist": "Bush",
+      "title": "Glycerine"
+    },
+    {
+      "rank": 5,
+      "artist": "Collective Soul",
+      "title": "Shine"
+    },
+    {
+      "rank": 6,
+      "artist": "Everclear",
+      "title": "Santa Monica (Watch The World Die)"
+    },
+    {
+      "rank": 7,
+      "artist": "Green Day",
+      "title": "Longview"
+    },
+    {
+      "rank": 8,
+      "artist": "Red Hot Chili Peppers",
+      "title": "Under the Bridge"
+    },
+    {
+      "rank": 9,
+      "artist": "Tom Petty And The Heartbreakers",
+      "title": "Waiting For Tonight"
+    },
+    {
+      "rank": 10,
+      "artist": "Rancid",
+      "title": "Ruby Soho"
+    },
+    {
+      "rank": 12,
+      "artist": "No Doubt",
+      "title": "Just A Girl"
+    },
+    {
+      "rank": 13,
+      "artist": "Dave Matthews Band",
+      "title": "Satellite"
+    },
+    {
+      "rank": 16,
+      "artist": "Ozzy Osbourne",
+      "title": "See You On The Other Side"
+    },
+    {
+      "rank": 18,
+      "artist": "Radiohead",
+      "title": "High And Dry"
+    },
+    {
+      "rank": 19,
+      "artist": "AC/DC",
+      "title": "Cover You In Oil"
+    },
+    {
+      "rank": 20,
+      "artist": "Goo Goo Dolls",
+      "title": "Naked"
+    },
+    {
+      "rank": 22,
+      "artist": "Poe",
+      "title": "Trigger Happy Jack (Drive By A Go-Go)"
+    },
+    {
+      "rank": 23,
+      "artist": "Alanis Morissette",
+      "title": "Ironic"
+    },
+    {
+      "rank": 24,
+      "artist": "Natalie Merchant",
+      "title": "Wonder"
+    },
+    {
+      "rank": 25,
+      "artist": "Tori Amos",
+      "title": "Caught A Lite Sneeze"
+    },
+    {
+      "rank": 26,
+      "artist": "For Squirrels",
+      "title": "Mighty K.C."
+    },
+    {
+      "rank": 28,
+      "artist": "Alice In Chains",
+      "title": "Grind"
+    },
+    {
+      "rank": 29,
+      "artist": "Loud Lucy",
+      "title": "Ticking"
+    },
+    {
+      "rank": 30,
+      "artist": "Silverchair",
+      "title": "Pure Massacre"
+    }
+  ]
+}