fix(kyberforge): carry apostrophes verbatim through a |- literal block

The flattener's last-resort branch rewrote ASCII ' to U+2019, justified as the
one combination no YAML scalar can carry verbatim. That claim was false: a |-
literal block with a single indented content line carries ', ", \ and ": "
verbatim and keeps text.frontmatter.description matching — as the wrapper's own
docstring already said of literal blocks. The rewrite fired on 12 of 54
in-scope files, silently disabling every rule whose token contains an
apostrophe. Case 20 pinned only that the scope stayed alive, so it passed
either way.

The emission site now splits the emitted scalar on its first newline so a
carried-over trailing comment stays on the "description: |-" header line rather
than becoming part of the value, and pads by span_lines - 1 - newlines. The pad
stays non-negative because the branch is only reachable when the original span
is at least two lines. Verified across all 73 in-scope files: no line-count
changes, and exactly the 12 expected files take the new branch.

One reported position moves: an alert on a description that is itself flagged
shifts from the key line to the block's content line, both inside the original
span. YAML cannot put a literal block's content on the key's own line, so this
is unavoidable; no line at or after the end of any description span moves.

Also: --output no longer absolutises the built-in style names line, JSON and
CLI, which a same-named file or directory in cwd turned into a template path
(exit 2, E100 Runtime error). And case 19's empty-baseline guard no longer
lets five dependent comparisons print vacuous passes — while fixing it the
guard turned out to be unreachable, since under pipefail an alert-free report
aborted the script at the assignment.

Refs: #85
ADR: 0014

docs/adr/0014-vale-prefilter-ships-from-the-plugin.md

@@ -168,3 +168,21 @@ that makes the two disagree already touches `$HOOKS_MANIFEST`, itself a release-
 unreadable tagged tree (shallow clone, truncated fetch) fails closed rather than silently degrading
 to worktree-only derivation; a manifest simply absent at the tag — legitimate, it was added since —
 does not.
+
+**Update — the flattener rewrites no characters.** This ADR never recorded it as a decision, but
+`vale-wrap.sh`'s flattener carried a lossy last-resort branch: when a description needed quoting
+*and* held an ASCII apostrophe *and* held a double quote or backslash, it substituted U+2019 (`’`)
+for every `'` before writing the scratch copy, on the stated rationale that no verbatim YAML scalar
+could carry that combination. The rationale was wrong. A `|-` literal block with a single indented
+content line carries `'`, `"`, `\` and `: ` byte for byte — a block scalar's body has no escape
+syntax at all — and vale's `text.frontmatter.description` scope still matches and fires rules on it
+(verified against vale 3.15.2; it is the same property that makes the `|` blocks in the wrapper's
+header safe to leave unflattened). The branch fired on 12 of the 54 in-scope files in this repo,
+silently disabling every rule whose token contains an apostrophe on each of them. The flattener now
+emits that literal block instead, so its output is verbatim in all four forms and no Vale rule can
+be silently disabled by the prefilter. The `|-` form is two physical lines where the three inline
+forms are one, so the blank-line pad that preserves later line numbers drops by one — reachable
+only when the original span is already two or more lines, so the pad count stays non-negative.
+`tests/test-vale-wrap.sh` case 20 asserts an apostrophe-bearing token actually fires on a flattened
+description in all three apostrophe-carrying branches, and case 20b pins the pad arithmetic against
+a body line's true line number.