fix(gen-skill-docs): preserve embedded periods in catalog leads

[time-attack]

What it does

Skill catalogs keep the full first sentence when it contains a filename, URL, or version, while preserving the following routing guidance.

How it works

The generator treats punctuation inside a token as embedded, then ends the lead at the first punctuation followed by whitespace or end-of-text. Templates are regenerated so committed catalogs match the corrected split.

What was broken

Skill descriptions containing filenames, URLs, or version numbers could be split at the wrong place, hiding the guidance agents use to choose a skill.

How it was fixed

The catalog now recognizes embedded periods without mistaking them for sentence endings. The production matcher was corrected, the known-limitation test was replaced with exact filename/version behavior, URL coverage was added, the diagram template boundary was clarified, and generated artifacts were refreshed.

Live evidence

The isolated baseline/candidate gate used an immutable origin/main snapshot and separate HOME roots.

Repository	Baseline	Candidate	Outcome
garrytan/gbrain	1	0	fail-to-pass
actionbook/actionbook	1	0	fail-to-pass
0xNyk/lacp	1	0	fail-to-pass
calcom/cal.com control	0	0	stayed pass
makeplane/plane control	0	0	stayed pass

Candidate commands were byte-identical to their stored baseline commands. The final evidence gate passed after the commit and report fingerprint was refreshed.

Secondary checks

• bun test test/catalog-trim.test.ts: 21 passed, 0 failed
• bun run gen:skill-docs --host codex: passed
• bun run build: passed
• git diff --check: passed

No version or release files were changed.

Closes garrytan#2171.