fix(code-intelligence): preserve shared runtime startup

[ZhiXiao-Lin]

Summary

• keep cold language-runtime startup single-flight when the initiating query is abandoned
• make startup, source removal, and workspace shutdown generation-aware and bounded
• prevent stale tasks from publishing late Ready state and publish complete per-language status
• prepare Core, Node, and Python artifacts for 5.3.3 without regressing the 5.3.2 release workflow

Validation

• release preflight: passed with isolated ACL fixture; real-provider smoke explicitly skipped because no credentials were available
• cargo clippy -p a3s-code-core --all-targets -- -D warnings
• cargo test --workspace
• cargo test --workspace --all-features --lib, plus three repeated all-feature runs
• 223/223 SemVer checks against published 5.3.2
• Node SDK runtime, helper, type, and example checks
• Python bootstrap tests
• actionlint and release-version consistency checks