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/VisualObserverTests.swift

@@ -11,6 +11,27 @@ final class VisualObserverTests: XCTestCase {
         (id, CGRect(x: 0, y: 0, width: w, height: h))
     }
 
+    func testCanonicalizeFoldsOcrMisspellingsIntoDominantName() {
+        func seg(_ s: Double, _ e: Double, _ n: String) -> VisualTimeline.Segment {
+            .init(start: s, end: e, name: n, confidence: 0.9, source: "vision")
+        }
+        let segs = [
+            seg(0, 1689, "Matt Odell"),   // dominant
+            seg(1700, 1702, "Matt Odel"), // OCR typo → fold
+            seg(1702, 1702.3, "MattOdell"), // dropped-space typo → fold
+            seg(0, 1155, "Mark"),         // dominant
+            seg(1200, 1201, "Mare"),      // OCR typo → fold into Mark
+            seg(0, 4, "Sidisel"),         // screen junk, no near-twin → kept (dropped later, no voice match)
+        ]
+        let names = Set(TimelineBuilder.canonicalizeByFrequency(segs).map { $0.name })
+        XCTAssertTrue(names.contains("Matt Odell"))
+        XCTAssertTrue(names.contains("Mark"))
+        XCTAssertFalse(names.contains("Matt Odel"))
+        XCTAssertFalse(names.contains("MattOdell"))
+        XCTAssertFalse(names.contains("Mare"))
+        XCTAssertTrue(names.contains("Sidisel"))
+    }
+
     func testPrefersMatchingWindowIDOverLargest() {
         // The Meet window (id 42) is NOT the largest — must still be chosen by ID.
         let candidates = [c(7, 1600, 1000), c(42, 800, 600), c(9, 1200, 900)]