fix(vscode): restore fresh prompt history recall

[dengbushi]

Fixes #11945

What changed

Restore the newest prompt to keyboard history when it is the first message in a new chat.

Root cause

This regressed in fbe5f4cb from #11442. During the first send, session.sendMessage() synchronously changes the draft key from :new to :pending:<uuid>. PromptInput checked that key before appending the sent draft to history, so the guard returned early and skipped the append.

The fix moves only history.append(draft) before that changed-key guard. Dispatch still happens first, and the guard continues to protect the later UI cleanup/reset from stale state.

Validation

• Focused prompt-history suites: 38 passed, 0 failed.
• Extension typecheck, lint, Prettier check, and knip passed.
• Repository pre-push typecheck passed, including the JetBrains package.

Local limitations

The full VS Code unit suite reproducibly had 39 failures in this Windows environment outside the touched tests (symlink, POSIX-path, and shell-environment assumptions); no clean-main baseline was run, so they are not claimed as pre-existing. A local development extension launch was also not completed because the Windows CLI build path was unavailable, so manual ArrowUp verification is not claimed.

[kilo-code-bot]

Code Review Summary

Status: No Issues Found | Recommendation: Merge

Files Reviewed (3 files)

• .changeset/restore-vscode-prompt-history.md
• packages/kilo-vscode/tests/unit/prompt-input-connection-guard.test.ts
• packages/kilo-vscode/webview-ui/src/components/chat/PromptInput.tsx

Previous Review Summary (commit 62a89f2)

Current summary above is authoritative. Previous snapshots are kept for context only.

Previous review (commit 62a89f2)

Status: No Issues Found | Recommendation: Merge

Files Reviewed (3 files)

• .changeset/restore-vscode-prompt-history.md
• packages/kilo-vscode/tests/unit/prompt-input-connection-guard.test.ts
• packages/kilo-vscode/webview-ui/src/components/chat/PromptInput.tsx

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_{Reviewed by gpt-5.6-sol-20260709 · Input: 56.4K · Output: 5.8K · Cached: 358.6K}

_{Review guidance: REVIEW.md from base branch main}

[dengbushi]

Closing this PR because it has been superseded by #12201, which merged the same root-cause fix: record history.append(draft) after dispatch but before the draft-key guard. #12201 also includes equivalent regression coverage and a changeset, so retaining this PR would duplicate code, tests, and release notes.