feat(board)!: rank --plan on five ordered groups, planned above in-progress

Replaces the weighted score shipped in 0.19.0 with five lookups: chain-root
credit, unhandled inbox, planned, in-progress, undeclared status. Within a
group: that group's own quantity, then a Sonnet next-cost, then oldest plan.

The score's objection is accepted, not forgotten, and is written into board.sh
and CLAUDE.md so a later session reads it as decided rather than as an unfixed
defect: a group order cannot express "owes one message AND releases two others"
as one quantity. What the score could not do was hold still for the format's
second consumer - re-tuning one weight against another silently reorders a
parser in another repo, and no test here can catch that.

planned now ranks above in-progress, inverted by the same decision: converting a
decision into motion is the slow step; live work is already moving.

Debt stays uncapped and never excluded. One group below chain-root credit is not
the cap declined at 0.19.0 - the debtor keeps its tab, its most-owed-first
position, and its why=inbox:N. Pinned by a discriminating fixture the score
would fail: a root releasing one repo outranks a repo owing four.

board-selftest 134 -> 138. Suite 183 + 138 + 73 = 394.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Y6ULuFCPMNYAPNN3pAjsXQ

CHANGELOG.md

@@ -5,6 +5,53 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [0.20.0] - 2026-08-03
+
+### Changed
+
+- **`--plan` ranks on FIVE ORDERED GROUPS, replacing the weighted score shipped
+  one version earlier.** The groups are chain-root credit, unhandled inbox,
+  `planned`, `in-progress`, and undeclared status — each a lookup over a field
+  the scan already read, so a selftest pins an outcome rather than a
+  coefficient. Within a group: the quantity that group is about, then a Sonnet
+  `next-cost`, then oldest plan first.
+
+  The objection the score answered is **accepted, not forgotten**, and is
+  recorded in `board.sh` and `CLAUDE.md` so it is read as decided rather than as
+  an unfixed defect: a group order genuinely cannot express "owes one message
+  **and** releases two others" as a single quantity. What the score could not do
+  was hold still for the format's second consumer — re-tuning 40 against 15
+  silently reorders a parser living in another repo, and no test here can catch
+  that. Operator decision, 2026-08-03.
+
+- **`planned` now ranks ABOVE `in-progress`**, inverted from every earlier
+  version by the same decision. A decided but unstarted next step is the step
+  that converts a decision into motion; live work is already moving. Flipping it
+  back is a policy change, not a sort fix.
+
+- **`why=` names the group that admitted the repo**, not the dominant scoring
+  term. The emitted values are unchanged (`unblocks:N`, `inbox:N`, `planned`,
+  `in-progress`, `uavklart`), so neither consumer sees a new token — but the
+  chain-root group is tested first, so `why=unblocks:N` now wins for **any**
+  root, not only where its weight happened to dominate.
+
+- **The Sonnet `next-cost` tiebreak introduced with the score is carried
+  forward deliberately**, demoted to the last key below group and magnitude. It
+  is a lookup, and removing a shipped property nobody asked to remove would be
+  the larger surprise. It can now only separate repos that are otherwise equal.
+
+### Notes
+
+- **Debt is still neither capped nor excluded.** Being one group below
+  chain-root credit is not the cap that was proposed and declined at 0.19.0: a
+  debtor keeps its tab, its most-owed-first position among the other debtors,
+  and its `why=inbox:N`. Selftest section 12 pins both halves on a
+  discriminating fixture — a root releasing **one** repo outranks a repo owing
+  **four** (which the score would have ordered the other way), and that debtor
+  keeps everything it had.
+- `board-selftest.sh` is 134 → **138 checks**. Suite total 183 + 138 + 73 =
+  **394**.
+
 ## [0.19.0] - 2026-08-02
 
 ### Added