Add real-world specimens and cross-links between sins

Two new levers on a sin page. `wild[]` renders credited, linked
specimens between the explanation and the citations — first the
argument, then proof people actually publish this, then the sources.
`related[]` cross-links neighbouring sins and is resolved at build, so a
typo fails the build instead of shipping a dead link.

Both arrive with the first specimen: a Hungarian primary graphic whose
three slices read 38/22/19 — 79% — drawn as a full circle, so every
share is inflated by about 1.27x. Measured off the image, the 38% slice
occupies 173.6 degrees, or 48.3% of the pie.

Our published pie sin is about too many slices, so it didn't cover this;
"Pie Slices That Don't Sum to the Whole" is a new severity-5 page whose
before/after is two pies differing only in whether the remainder is
present. That sin is an omission, so `compareNote` replaces the standard
"same numbers, both charts" line.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01ULE5RRxdQE1ebwefEd2eCM

docs/content-backlog.md

@@ -17,7 +17,7 @@ runs 2–5 on purpose.
 
 ## Sources in play
 
-`src/lib/references.ts` currently holds 24 entries, 20 of them cited by the five
+`src/lib/references.ts` currently holds 24 entries, 21 of them cited by the 6
 published sins. This table is a **convenience, not a scoreboard** — it's here so
 you can spot a source that fits a sin you're drafting, not so we can drive the
 right-hand column to zero blanks. An uncited reference is not a debt.
@@ -29,26 +29,26 @@ seven sources, give it seven and add whatever's missing to the file.
 | --- | --- |
 | `ftvisvocab` | — |
 | `healy` | — |
-| `munzner` | — |
 | `schwabish` | — |
 | `fewdualaxes` | dual-axis-correlation |
-| `fewpies` | too-many-pie-slices |
 | `huff` | truncated-y-axis |
 | `isenberg2011` | dual-axis-correlation |
+| `munzner` | incomplete-pie |
 | `shapeparameter` | aspect-ratio |
 | `showmenumbers` | too-many-pie-slices |
 | `spurious` | dual-axis-correlation |
 | `swd` | dual-axis-correlation |
 | `tufte` | truncated-y-axis |
-| `vizwtf` | inverted-y-axis |
 | `callingbullshit` | inverted-y-axis, truncated-y-axis |
-| `datatoviz` | dual-axis-correlation, too-many-pie-slices |
-| `datawrapper` | dual-axis-correlation, too-many-pie-slices |
 | `eagereyes` | aspect-ratio, too-many-pie-slices |
+| `fewpies` | incomplete-pie, too-many-pie-slices |
 | `junkcharts` | inverted-y-axis, too-many-pie-slices |
 | `truthfulart` | aspect-ratio, dual-axis-correlation |
+| `vizwtf` | incomplete-pie, inverted-y-axis |
 | `wilke` | too-many-pie-slices, truncated-y-axis |
 | `clevelandmcgill` | aspect-ratio, too-many-pie-slices, truncated-y-axis |
+| `datatoviz` | dual-axis-correlation, incomplete-pie, too-many-pie-slices |
+| `datawrapper` | dual-axis-correlation, incomplete-pie, too-many-pie-slices |
 | `economistmistakes` | dual-axis-correlation, inverted-y-axis, truncated-y-axis |
 | `howchartslie` | aspect-ratio, dual-axis-correlation, inverted-y-axis, truncated-y-axis |
 
@@ -74,7 +74,32 @@ we can build.
 **Citations:** `huff` (the original con), `callingbullshit`, `howchartslie`,
 `junkcharts`.
 
-### 2. Pie Slices That Sum to More Than 100% — *Impossible Wholes*, severity 5
+### 2. Results From a Hand-Picked Subgroup — *Deceptive Framing*, severity 4
+
+**Poke:** "You didn't pick the wrong chart, you picked the wrong people. The
+number is real; the group it describes was chosen after the fact."
+
+The population-shaped twin of entry 1. Rather than trimming the time window, you
+report the slice of the audience, region or segment where the number flatters —
+often labelled honestly, which is what makes it feel above board.
+
+The published `incomplete-pie` specimen is **also an example of this one**: it
+reports the primary "in the countryside," excluding the capital, on a graphic
+whose banner argues the capital can't win. Reuse the same image here with a note
+about this failure mode — that's what the `wild` array is for, and it's the case
+for keeping these as two pages rather than one.
+
+Worth its own page rather than folding into entry 1: the tell is different (no
+axis to inspect — you have to know what got left out), and the fix is different
+(report the whole population, or every subgroup side by side, not just the
+flattering one).
+
+**Charts:** bad = one subgroup's result. Fixed = every subgroup plus the overall
+figure, same underlying data.
+
+**Citations:** `callingbullshit`, `howchartslie`, `huff`, `vizwtf`.
+
+### 3. Pie Slices That Sum to More Than 100% — *Impossible Wholes*, severity 5
 
 **Poke:** "Your slices add up to 180%. A pie has one job — dividing a whole —
 and this data has no whole to divide."
@@ -97,7 +122,7 @@ pie-chart post says "one pie chart can only show one total and its shares," and
 it does *not* separately argue that parts must be mutually exclusive. Don't
 stretch it further than that. Plus `datatoviz`, `junkcharts`.
 
-### 3. A Pie Chart of Rates or Averages — *Impossible Wholes*, severity 5
+### 4. A Pie Chart of Rates or Averages — *Impossible Wholes*, severity 5
 
 **Poke:** "You made a pie out of averages. Adding them together produces a
 number that means nothing, and that number is your denominator."
@@ -120,7 +145,7 @@ same averages, plus the volume behind each one so the weighting is visible.
 or it is nothing), `datawrapper` (same one-total premise as above), `schwabish`,
 `ftvisvocab`.
 
-### 4. Group Averages Shown Without the Distribution — *Hiding the Data*, severity 4
+### 5. Group Averages Shown Without the Distribution — *Hiding the Data*, severity 4
 
 **Poke:** "Four bars, four averages, and no idea whether the difference is real."
 
@@ -133,7 +158,7 @@ observations, means still marked.
 
 **Citations:** `wilke`, `healy`, `schwabish`, `datatoviz`.
 
-### 5. Bubbles Sized by Radius Instead of Area — *Perceptual Traps*, severity 4
+### 6. Bubbles Sized by Radius Instead of Area — *Perceptual Traps*, severity 4
 
 **Poke:** "You doubled the number and quadrupled the ink."
 
@@ -148,7 +173,7 @@ position does the work.
 
 **Citations:** `munzner`, `clevelandmcgill`, `tufte`, `howchartslie`.
 
-### 6. Stacked Segments Without a Shared Baseline — *Perceptual Traps*, severity 3
+### 7. Stacked Segments Without a Shared Baseline — *Perceptual Traps*, severity 3
 
 **Poke:** "Only the bottom band of a stacked chart has a straight edge to
 measure against. The rest are guesses."
@@ -175,7 +200,7 @@ out to its own zero baseline), totals preserved.
 
 **Citations:** `datawrapper`, `wilke`, `munzner`, `ftvisvocab`.
 
-### 7. Categories Sorted Alphabetically Instead of by Value — *Sloppy Craft*, severity 2
+### 8. Categories Sorted Alphabetically Instead of by Value — *Sloppy Craft*, severity 2
 
 **Poke:** "Your categories are sorted by name. Nobody wants to know which
 region starts with A."
@@ -210,6 +235,16 @@ rediscovering them:
   too: the fixed chart needs a sequential ramp validated on `--chart-canvas` in
   both themes. Don't draft this one until a real source is in hand.
 
+## Two new levers, as of the first wild specimen
+
+- **`wild`** — real examples, credited and linked, rendered above the citations.
+  Zero, one or many per sin. A specimen that commits two sins belongs on both
+  pages, with a different note on each; that's a reason to split sins, not merge
+  them.
+- **`related`** — cross-links between sins, validated at build. Charts rarely
+  break one rule at a time, and the person you sent a link to may need the
+  neighbouring page more than the one they landed on.
+
 ## Conventions reminder
 
 Note what the two pie entries above do and don't say. Neither condemns the pie