fix(card): donut legend caps at 7 rows (Other inclusive); add heatmap gutter (#20)

Two follow-ups:

1. "Top 7 languages" counts rows the reader sees, not "7 named + Other".
   Revert collapseOther to the original semantic: when the input has more
   than n entries, keep in[:n-1] named and fold the tail into a single
   "Other" row — 7 rows total with topN=7. Input with ≤7 real languages
   still passes through unchanged. Test and adversarial-profile updated
   to pin the cap (6 named + Other, Shell/Kotlin/Java collapse).

2. Contributions heatmap grid was touching the card right edge
   (leftPad 22 + 53*6 = 340 exactly). Shrink cells from 5×5 to 4×4 and
   bump leftPad to 30, giving 45 px of right gutter. Grid no longer
   reads as bleeding into the frame border; weekday label column also
   gets a few more pixels of breathing room on the left.

docs/design-guidelines.md

@@ -50,7 +50,7 @@ Cap rows at what fits: up to 7 rows per card. Stats splits commits into lifetime
 | Donut centre | `(250, 110)` |
 | Outer radius | 55 |
 | Inner radius | 30 |
-| Top-N entries shown | Up to 7 named languages, plus an "Other" row when the tail is non-zero (8 rows max) |
+| Top-N entries shown | 7 rows max, "Other" inclusive (6 named + "Other" when there's a tail, up to 7 named when there isn't) |
 | Slice stroke | `theme.Background`, 1.5 px (gap between slices) |
 | Legend origin | `(20, 55)` |
 | Legend row height | 20 px |
@@ -78,7 +78,7 @@ When there's **exactly one slice** (one language at 100%), the renderer emits tw
 | Metric | Value |
 | --- | --- |
 | Grid | 7 rows × 53 columns (Sunday → Saturday, oldest week → newest) |
-| Cell size | 5 × 5 px, 1 px gap (exact fit: `leftPad(22) + 53 × 6 = 340`) |
+| Cell size | 4 × 4 px, 1 px gap. Grid footprint = `53 × 5 = 265 px`; `leftPad(30) + 265 = 295 px`, leaving a 45 px right gutter so the grid doesn't bleed into the frame border |
 | Cell colour | 5-bucket ramp `mixHex(Background, Accent, k/4)` for `k ∈ 0..4` — no dedicated ramp field on the theme schema |
 | Weekday labels | Mon / Wed / Fri only, right-anchored in the `leftPad` gutter |
 | Month labels | Printed above the first week where a 1st-of-month day falls; skipped when `x > width − 20` so `Dec` / `Apr` can't spill past the frame |

internal/card/card_test.go

@@ -141,11 +141,10 @@ func TestDonutEmpty(t *testing.T) {
 	}
 }
 
-// TestDonutTopSevenPlusOther confirms the "7 named + Other" contract: when
-// the input has more than 7 languages, the legend shows all 7 real entries
-// followed by a single "Other" bucket. Regression guard against anyone
-// sliding topN back to "N-1 real + Other" packing.
-func TestDonutTopSevenPlusOther(t *testing.T) {
+// TestDonutMaxSevenRows confirms the legend caps at 7 rows (Other inclusive):
+// 9 input languages collapse to the top 6 named + "Other". Regression guard
+// against anyone flipping the collapse semantic back to "7 named + Other".
+func TestDonutMaxSevenRows(t *testing.T) {
 	th, _ := theme.Lookup("dracula")
 	stats := []github.LangStat{
 		{Name: "Go", Color: "#00ADD8", Value: 100},
@@ -159,13 +158,13 @@ func TestDonutTopSevenPlusOther(t *testing.T) {
 		{Name: "Java", Color: "#b07219", Value: 20},
 	}
 	svg := string(renderDonutCard("Test", stats, th))
-	for _, want := range []string{"Go", "TypeScript", "Python", "Rust", "JavaScript", "HTML", "Shell", "Other"} {
+	for _, want := range []string{"Go", "TypeScript", "Python", "Rust", "JavaScript", "HTML", "Other"} {
 		if !strings.Contains(svg, ">"+want+" ") {
 			t.Errorf("expected legend row for %q; not found in:\n%s", want, svg)
 		}
 	}
-	// Kotlin + Java spill into Other (they must NOT appear as named rows).
-	for _, dropped := range []string{">Kotlin ", ">Java "} {
+	// Shell, Kotlin, Java are outside the top 6 and roll into Other.
+	for _, dropped := range []string{">Shell ", ">Kotlin ", ">Java "} {
 		if strings.Contains(svg, dropped) {
 			t.Errorf("expected %q to be collapsed into Other, but it renders:\n%s", dropped, svg)
 		}

internal/card/contributions_heatmap.go

@@ -22,15 +22,16 @@ func (contributionsHeatmapCard) SVG(p *github.Profile, t theme.Theme) ([]byte, e
 // theme.Accent in four intensity buckets so every palette inherits a usable
 // heatmap without a separate color ramp in the theme schema.
 //
-// Geometry is sized so 53 weeks fit inside the 340 px frame:
-// leftPad (22) + 53*(cellSize+cellGap)=53*6=318 → grid ends at x=340.
+// Geometry: 4 px cells + 1 px gap = 5 px per week column × 53 weeks = 265 px.
+// Left pad 30 (weekday labels), right pad 45 — both well clear of the frame
+// so the grid doesn't read as "bleeding" off the card.
 func renderHeatmap(title string, days []github.DailyContribution, t theme.Theme) []byte {
 	const (
 		width    = 340
 		height   = 200
-		cellSize = 5
+		cellSize = 4
 		cellGap  = 1
-		leftPad  = 22
+		leftPad  = 30
 		topPad   = 62
 	)
 

internal/card/donut_chart.go

@@ -99,23 +99,21 @@ func polar(cx, cy float64, r, angle float64) (float64, float64) {
 	return cx + r*math.Cos(angle), cy + r*math.Sin(angle)
 }
 
-// collapseOther returns the top n named entries, optionally followed by an
-// "Other" row summing everything past that. "Top N" means N actual languages
-// — the Other row is a bonus when there's a non-zero tail, not one of the N.
-// When the input fits in N entries the caller gets the slice back as-is.
+// collapseOther caps the legend at n rows. If there are more than n inputs
+// it keeps the top (n-1) named slices and folds everything past that into a
+// single "Other" row — so n counts TOTAL rows (Other inclusive), matching
+// what readers count when they glance at the legend.
 func collapseOther(in []github.LangStat, n int) []github.LangStat {
 	if len(in) <= n {
 		return in
 	}
-	out := make([]github.LangStat, 0, n+1)
-	out = append(out, in[:n]...)
+	out := make([]github.LangStat, 0, n)
+	out = append(out, in[:n-1]...)
 	var rest int64
-	for _, s := range in[n:] {
+	for _, s := range in[n-1:] {
 		rest += s.Value
 	}
-	if rest > 0 {
-		out = append(out, github.LangStat{Name: "Other", Value: rest})
-	}
+	out = append(out, github.LangStat{Name: "Other", Value: rest})
 	return out
 }