fix(cli): unblock prebuilt release entrypoint (SyntaxError + init deadlock)

[continued-agent]

Problem

The prebuilt CLI bundle produced by npm run build crashes at module load with:

SyntaxError: Unexpected reserved word
    at compileSourceTextModule (node:internal/modules/esm/utils:346:16)

The Release CLI workflow (triggered by cli-v* tag pushes) was building the bundle successfully but failing at the Verify release entrypoint step, so cli-v0.1.0 could not be released.

Root cause

Circular static imports between three modules caused esbuild to emit a __esm factory for src/stream/streamChatResponse.autoCompaction.ts that contained a top-level await without the async keyword:

• src/compaction.ts <-> src/stream/streamChatResponse.ts (the former called streamChatResponse for streaming the summary; the latter used pruneLastMessage from the former).
• src/subagent/executor.ts static-imported streamChatResponse, adding a second cycle through the tools/subagent init chain.

The earlier minifySyntax: false fix only stopped esbuild from mangling the keyword; it did not remove the cycle. With the cycle removed, a second symptom surfaced in the form of a module-init deadlock (init_streamChatResponse waiting on init_subagent/executor waiting on init_streamChatResponse) that hung the bundled CLI indefinitely.

Fix

Break both cycles with the minimum number of files:

1. Extract pruneLastMessage into src/util/chatHistoryPrune.ts so the stream layer and the compaction helpers no longer share a static edge through compaction.ts.
2. Move compactChatHistory (and the related COMPACTION_PROMPT / Compaction* types) into a new src/stream/streamChatResponse.compactChatHistory.ts so compaction.ts becomes a leaf with no dependency on the stream layer, and streamChatResponse.autoCompaction.ts no longer reaches streamChatResponse.ts through compaction.ts.
3. Resolve streamChatResponse at call time through a late-bound streamChatResponseRef (new src/stream/streamChatResponse.lateRef.ts) from both compactChatHistory.ts and subagent/executor.ts, so neither module has a static import back into streamChatResponse.ts.

streamChatResponse.ts registers itself in the ref at the end of its module factory, so consumers can call the function at runtime without creating a circular import.

Release validation

The release workflow now validates the exact artifact that will be published by copying dist/index.js, dist/cn.js, dist/xhr-sync-worker.js and a minimal {"type":"module"} package.json into a clean directory and running both node cn.js --help and node cn.js --version from there. The Create GitHub release step is only reached when both commands succeed and produce non-empty output. This catches parse errors, top-level await cycles, and missing-module issues before any release is published.

Tests

• node smoke-test.mjs (10/10 pass) — invokes the bundled dist/cn.js --help/--version and other entrypoint checks.
• npx vitest run — 1697/1697 tests pass, 29 skipped.
• npx tsc --noEmit — clean.
• npx eslint . — clean.
• Manual packaged-artifact test: copying the build output plus package.json to a clean directory and running node cn.js --help and node cn.js --version succeeds.

Files

• extensions/cli/src/util/chatHistoryPrune.ts (new) — leaf module for pruneLastMessage.
• extensions/cli/src/stream/streamChatResponse.compactChatHistory.ts (new) — compactChatHistory and types.
• extensions/cli/src/stream/streamChatResponse.lateRef.ts (new) — late-bound streamChatResponseRef.
• extensions/cli/src/compaction.ts — re-exports pruneLastMessage for back-compat; no longer imports streamChatResponse.
• extensions/cli/src/stream/streamChatResponse.ts — registers itself in the ref.
• extensions/cli/src/stream/streamChatResponse.autoCompaction.ts, extensions/cli/src/subagent/executor.ts, extensions/cli/src/ui/hooks/useChat.compaction.ts, extensions/cli/src/commands/chat.ts — updated imports.
• Tests updated to mock the new file paths and register the ref in beforeAll where needed.
• .github/workflows/release-cli.yml — combined verify/package step tests the exact published artifact (--help and --version) in a clean directory; release is gated on success.
• extensions/cli/README.md, extensions/cli/CHANGELOG.md — document the packaging/validation process.