[Improve] Allow trailing punctuation on kickoff messages

[roomote-roomote]

Opened on behalf of Matt Rubens. Follow up by mentioning @roomote-roomote, in the web UI, or in Slack.

Related issue

N/A — internal product copy change from maintainer request.

Why this PR exists

• A maintainer explicitly invited this PR in the linked issue or discussion
• I am a maintainer / this is internal Roomote work

What changed

Stop forbidding trailing punctuation on router kickoff messages.

• Removed the “no trailing period” rule from the routing prompt, response schema, and router eval prompt
• Stopped normalizeKickoffMessage from stripping trailing periods so freeform kickoffs keep the model’s punctuation
• Existing safety normalization (mentions, quotes, length) is unchanged

How it was tested

• pnpm --filter @roomote/communication exec vitest run src/__tests__/chat-messages.test.ts
• pnpm --filter @roomote/slack exec vitest run src/__tests__/block-kit.test.ts

Checklist

• The PR title follows the repo convention: [Fix], [Feat], [Improve], [Refactor], [Docs], or [Chore] followed by a user-facing description
• This PR is small and scoped to one change
• pnpm lint and pnpm check-types pass locally
• I added tests or included a clear manual validation note above
• I removed secrets, tokens, private keys, and customer data from code, logs, and screenshots
• If this change should appear in the changelog, I ran pnpm changeset

Impact

When the router writes a short kickoff sentence with a trailing period, chat started messages can show that period instead of forcing a period-free status phrase.

[roomote-roomote]

No code issues found. See task

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