Fix Meet visual: reject solid avatar tiles + screen-share OCR

Root cause of the "4 people → 2 speakers" Meet call: the colored-border detector
read solid camera-off avatar tiles (orange "J", magenta "G") as active speakers
for the ENTIRE call. Those whole-call phantom spans dominated backend name
attribution, collapsing every remote voice onto one name — and the giant filled
bbox also swallowed screen-share text (WERUNBTC.COM ×49) as a speaker.

Validated against 9 real fixtures (harness over the real MeetAdapter):

Detection:
- FrameSampler.thinColoredPoints: coloured counterpart of thinWhitePoints — keeps
  thin border/ring/pill edges, drops solid colour fills.
- GridCallAnalyzer.isHollow: reject a highlight component whose interior is filled
  (a solid tile) vs a hollow ring (a real border). Config.maxInteriorFill (0.2 default).
- MeetAdapter: detect thin BLUE edges only (hue 180–240°, measured from the
  fixtures), maxInteriorFill 0.3 (real Meet rings ≈0.2–0.3, solid tiles ≈0.36).
- Result on fixtures: John Arnold/Grant Gilliam (solid tiles) now NEVER detected;
  Matt Odell/Mark detected when their blue cue is present. Sparse but never wrong —
  correct for a naming hint over audio diarization.

OCR name hygiene:
- isLikelyName rejects domain-like screen-share text ("WERUNBTC.COM", OCR'd ".GOM").
- cleaned() strips trailing punctuation ("Mark." → "Mark").
- TimelineBuilder.canonicalizeByFrequency folds rare OCR misspellings into a
  dominant near-twin name ("Matt Odel"/"MattOdell" → "Matt Odell", "Mare" → "Mark").

Tests: hollow-ring, extended OCR filter, fuzzy-merge. 65 pass.

Ten31TranscriptsTests/GridCallAnalyzerTests.swift

@@ -138,16 +138,37 @@ final class GridCallAnalyzerTests: XCTestCase {
     func testNameFilterAgainstRealMeetOCR() {
         // The exact strings OCR pulled from a real Meet session — only the first
         // group are participants; the rest are UI chrome that must NOT become speakers.
-        let names = ["Grant Gilliam", "Caitlyn Viggiano", "Cait's Phone", "Grant", "Me"]
+        let names = ["Grant Gilliam", "Caitlyn Viggiano", "Cait's Phone", "Grant", "Me", "Matt Odell"]
         let junk = ["11:43 AM | rvo-rmjg-rdq", "@ Embassy Er", "Admit 1 guest",
                     "Joined as grant.gilliam@gmail.com", "Others may see your video differently",
                     "Others might still see your full video.", "Your meeting's ready", "efforot",
                     "g* Add others", "g+ Add others", "meet.google.com/rvo-rmjg-rdq",
-                    "permission before they can join.", "the meeting", "G"]
+                    "permission before they can join.", "the meeting", "G",
+                    // Screen-share domain text OCR'd as a name (incl. OCR'd TLDs).
+                    "WERUNBTC.COM", "WERUNBTG.COM", "WERUNBTC.GOM"]
         for n in names { XCTAssertTrue(GridCallAnalyzer.isLikelyName(n), "should keep name: \(n)") }
         for j in junk { XCTAssertFalse(GridCallAnalyzer.isLikelyName(j), "should drop junk: \(j)") }
     }
 
+    func testHollowRingKeptFilledTileRejected() {
+        // A thin ring (border): points only on the perimeter of a 120×120 box.
+        var ring: [CGPoint] = []
+        for t in stride(from: 0.0, through: 120, by: 4) {
+            ring.append(.init(x: t, y: 0));   ring.append(.init(x: t, y: 120))
+            ring.append(.init(x: 0, y: t));   ring.append(.init(x: 120, y: t))
+        }
+        let rbb = GridCallAnalyzer.boundingBox(ring)
+        XCTAssertTrue(GridCallAnalyzer.isHollow(ring, bbox: rbb, maxInteriorFill: 0.2))
+
+        // A solid fill (camera-off avatar tile): points across the whole box.
+        var blob: [CGPoint] = []
+        for x in stride(from: 0.0, through: 120, by: 4) {
+            for y in stride(from: 0.0, through: 120, by: 4) { blob.append(.init(x: x, y: y)) }
+        }
+        let bbb = GridCallAnalyzer.boundingBox(blob)
+        XCTAssertFalse(GridCallAnalyzer.isHollow(blob, bbox: bbb, maxInteriorFill: 0.2))
+    }
+
     func testWhiteBorderDetectorIgnoresColouredBorder() {
         // Signal looks only for the white border, so a coloured (Meet) border must
         // not register as a Signal speaker.