Enforce packaged clangd runtime

[cowboydaniel]

Summary

• package the clangd runtime asset into the APK and fail assembly when it is missing or non-executable
• load clangd from the packaged asset at runtime with explicit errors instead of placeholder fallbacks
• remove the demo fallback path and update Android build documentation to reflect the mandatory clangd bundle

Testing

• Not run (not requested)

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Codex Task

[chatgpt-codex-connector]

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[chatgpt-codex-connector]

Guard hover requests when language server not ready

The new maybeShowHelp path launches a hover request unconditionally; when clangd fails to start (e.g., packaged asset missing/non-executable) or is still initializing, RuntimeLanguageServerTransport.send immediately returns without emitting a response, so requestHover suspends forever and the coroutine never reaches the fallback docs dialog. Users who move the cursor before the LSP is ready will see the help UI hang silently and leak coroutines. Consider skipping the LSP call until status is Ready or timing out to fall back to the local docs.

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