docs: state the tagged state, because the tag is what these four sentences outlive

[jdatcmd]

Four documents said v1.0-alpha3 was the latest published pre-release. True at
the moment of writing, and false for the entire life of the v1.0-alpha4 tag that
is cut from this commit.

CHANGELOG.md:10   README.md:27   docs/roadmap.md:16   docs/installation.md:156

The timing is what decides it. The tag is cut FROM this tree, so whatever these
say is what the tag says permanently. Naming alpha4 is wrong for the minutes
between this commit and the tag. Naming alpha3 is wrong for as long as the tag
exists, and README is the first thing a reader opens.

v1.0-alpha2 and v1.0-alpha3 both shipped the older form, so the project has
published this three times. That is a reason to stop rather than a reason to
continue: #1043 and #1088 were both this same class, a document telling a reader
something the tree falsifies, and removing that class is most of two days' work.

Raised by @OffgridwithJD reviewing #1099. The half they left alone is the half
about default_version being in development, which changes at cycle-open rather
than at the tag. Those read as one sentence and are two claims with two clocks,
so the sentences are now split.

THE CHECK COULD NOT SEE ITS OWN REFERENCE DOCUMENT. docs_style.sh matched the
claim in one word order only. Three documents write "latest published pre-release
is vX" and CHANGELOG.md writes "vX is the latest published pre-release", so
the rule parsed the three copies and skipped the original. It compared the copies
to each other and exempted the one they are copied from.

Both orders are read now, and a file that states the claim in a form the rule
cannot parse is NAMED rather than skipped. Proved by mutation, both directions:

README disagrees        FAIL got [DISAGREE:v1.0-alpha3,v1.0-alpha9]
CHANGELOG unparseable   FAIL got [CHANGELOG.md]

The agreement check also compared "" against "" and passed when the extraction
came back empty. That is #1096's defect exactly, where the premise caught it and
the headline still reported PASS. It carries a distinct sentinel now. Raised by
@OffgridwithJD.

That rule then caught this change: splitting the sentence put the claim across two
lines, and grep is line-based, so two documents became unreadable to it. Rewrapped.

Verification:

docs_style.sh                   25 checks, PASSED
plain_language_check.py         0 failures across docs/, README, release notes
test_docs_cover_the_corpus.py   98 checks, 38 passed

---

🤖 Generated with Claude Code

https://claude.ai/code/session_01NhwXKAgSmYDUjteWkfajHK