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-1996-12-14.json

@@ -0,0 +1,156 @@
+{
+  "station": "Tunecaster Rock Top 30",
+  "date": "1996-12-14",
+  "tracks": [
+    {
+      "rank": 1,
+      "artist": "Soundgarden",
+      "title": "Blow Up The Outside World"
+    },
+    {
+      "rank": 2,
+      "artist": "Garbage",
+      "title": "#1 Crush"
+    },
+    {
+      "rank": 3,
+      "artist": "Stone Temple Pilots",
+      "title": "Lady Picture Show"
+    },
+    {
+      "rank": 4,
+      "artist": "311",
+      "title": "All Mixed Up"
+    },
+    {
+      "rank": 5,
+      "artist": "Cake",
+      "title": "The Distance"
+    },
+    {
+      "rank": 6,
+      "artist": "No Doubt",
+      "title": "Don't Speak"
+    },
+    {
+      "rank": 7,
+      "artist": "Tool",
+      "title": "Stinkfist"
+    },
+    {
+      "rank": 8,
+      "artist": "Bush",
+      "title": "Swallowed"
+    },
+    {
+      "rank": 9,
+      "artist": "Local H",
+      "title": "Bound For The Floor"
+    },
+    {
+      "rank": 10,
+      "artist": "The Smashing Pumpkins",
+      "title": "Thirty-Three"
+    },
+    {
+      "rank": 11,
+      "artist": "Red Hot Chili Peppers",
+      "title": "Love Rollercoaster"
+    },
+    {
+      "rank": 12,
+      "artist": "Alice In Chains",
+      "title": "Down in a Hole"
+    },
+    {
+      "rank": 13,
+      "artist": "Counting Crows",
+      "title": "A Long December"
+    },
+    {
+      "rank": 14,
+      "artist": "The Wallflowers",
+      "title": "One Headlight"
+    },
+    {
+      "rank": 15,
+      "artist": "Better Than Ezra",
+      "title": "Desperately Wanting"
+    },
+    {
+      "rank": 16,
+      "artist": "The Presidents Of The United States Of America",
+      "title": "Mach 5"
+    },
+    {
+      "rank": 17,
+      "artist": "Poe",
+      "title": "Hello"
+    },
+    {
+      "rank": 18,
+      "artist": "Kula Shaker",
+      "title": "Tattva"
+    },
+    {
+      "rank": 19,
+      "artist": "Luscious Jackson",
+      "title": "Naked Eye"
+    },
+    {
+      "rank": 20,
+      "artist": "Soul Coughing",
+      "title": "Super Bon Bon"
+    },
+    {
+      "rank": 21,
+      "artist": "Metallica",
+      "title": "Hero Of The Day"
+    },
+    {
+      "rank": 22,
+      "artist": "Sublime",
+      "title": "What I Got"
+    },
+    {
+      "rank": 23,
+      "artist": "Rush",
+      "title": "Half The World"
+    },
+    {
+      "rank": 24,
+      "artist": "Matchbox 20",
+      "title": "Long Day"
+    },
+    {
+      "rank": 25,
+      "artist": "The Bloodhound Gang",
+      "title": "Fire Water Burn"
+    },
+    {
+      "rank": 26,
+      "artist": "Phish",
+      "title": "Free"
+    },
+    {
+      "rank": 27,
+      "artist": "Fountains Of Wayne",
+      "title": "Radiation Vibe"
+    },
+    {
+      "rank": 28,
+      "artist": "Sponge",
+      "title": "Have You Seen Mary"
+    },
+    {
+      "rank": 29,
+      "artist": "John Mellencamp",
+      "title": "Just Another Day"
+    },
+    {
+      "rank": 30,
+      "artist": "Fiona Apple",
+      "title": "Shadowboxer"
+    }
+  ]
+}