chore(release): bump to 0.30.0

Two commits landed after v0.29.0 and neither is reachable: every entry point
on this machine runs the version-pinned plugin cache, not the tree.

Minor rather than patch because the behaviour is EXTENDED, not merely
repaired - coord-count.sh and board.sh gained a new exit status (3, "the
world you named is not there"), and pre-state-line-guard.mjs gained
CLAUDE_STATE_MAX_LINES. Exit codes are a contract, and the installed cache
still runs the old one.

Version synced across all seven version-bearing files - plugin.json,
package.json, the README badge, and the four SKILL.md frontmatters - so
release-plugin.mjs's plugin.json == README-badge == target check passes.
The three remaining 0.29.0 mentions (CLAUDE.md:915, CLAUDE.md:960,
board.sh:1388) are historical prose about when things shipped and must keep
saying 0.29.0.

CHANGELOG covers BOTH unreleased commits, not just the newest: d8fdeaa's
five defects were one class - a failed measurement rendering as a
reassuring value - and the entry carries what that session found about
itself, that --plan's free-capacity test had to move from "$7 + 0" to a
string comparison against "0", because "?" coerces to 0 in arithmetic and
would have certified an UNMEASURED tree as free capacity. The defect
reappearing one layer down, wearing the fix as a disguise.

No tag and no catalog change: that is the catalog session's order, which
runs release-plugin.mjs to do the tag and the ref bump atomically. Doing
both here would take a decision on the catalog's behalf without its
context.

Suites verified under system bash 3.2, not Homebrew 5.3: coord 242, board
300, route 69, orders 110, guard 54; npm test 11/11.

Order 20260826T115026Z-998059640-from-.claude

skills/route/SKILL.md

@@ -14,7 +14,7 @@ description: >-
   the operator names no model and no tool — choosing the model for the next
   session IS this skill. Not for choosing which REPO gets the next session:
   that is the `board` skill.
-version: "0.29.0"
+version: "0.30.0"
 ---
 
 # route — what the next session should run with