fix(release): harden packaged backends for v1.4.12

[Hello-QM]

Summary

• publish the immutable successor release metadata for CatGo 1.4.12
• make Linux PyInstaller bundles use one ABI-compatible conda libstdc++ / libgcc runtime pair and fail the build if collected native libraries require unsupported CXXABI or GLIBCXX symbols
• give the first frozen Campaign invocation a realistic Windows cold-start budget and terminate the complete PyInstaller process tree before temporary logs are removed
• add regression tests and a canonical full release Description for 1.4.12

Why 1.4.12

The v1.4.11 tag is immutable and its Desktop release smoke exposed two platform-specific blockers after tagging:

• Linux loaded conda ICU 78 against Ubuntu 22.04's older bundled libstdc++.so.6, which lacked CXXABI_1.3.15.
• Windows used the generic five-second HTTP timeout for the first frozen Campaign scaffold, then left the PyInstaller child holding backend.log, masking the timeout with WinError 32 during cleanup.

The existing v1.4.11 tag and draft release are intentionally left unchanged.

Verification

• python -m pytest server/tests/test_pyinstaller_runtime.py server/tests/test_smoke_frozen_catbot.py -q — 6 passed
• pnpm test:node — 360 passed
• node scripts/verify-release-version.mjs — 1.4.12 verified
• node scripts/verify-release-rights.mjs — 2 ledgers verified
• node scripts/verify-legal-distributions.mjs — 10 contracts and 27 files verified
• python -m py_compile server/pyinstaller_runtime.py scripts/smoke-frozen-catbot.py server/tests/test_pyinstaller_runtime.py server/tests/test_smoke_frozen_catbot.py
• git diff origin/main...HEAD --check

Release evidence

• Linux failure: https://github.com/Hello-QM/catgo-LRG/actions/runs/32859739223/job/97840468579
• Windows failure: https://github.com/Hello-QM/catgo-LRG/actions/runs/32859739223/job/97840468628