Fix cross-platform CI and Windows daemon launches

[RightL]

Summary

• Query the immediate Windows job policy before choosing detached-process flags: retain explicit breakaway when allowed, support silent breakaway and non-kill-on-close jobs, and refuse restrictive kill-on-close jobs instead of silently weakening daemon lifetime guarantees.
• Add policy-matrix and native Windows lifecycle regressions while retaining all existing integration tests.
• Update the DeepSeek profile test for the current conditional forced-tool-choice capabilities in pydantic-ai 2.52.0.
• Make the executable-backing-file undo fixture synchronize working-tree permissions with the Git index and assert it starts clean.

Validation

• Python 3.11.16: python -m compileall -q rightmemory tests passed.
• Local full Linux suite succeeded: 1,543 tests, 16 expected platform/optional-dependency skips.
• Frontend: typecheck passed; 57 tests passed via node --import tsx --test tests/*.test.ts; build and committed bundle consistency passed. The cloud sandbox blocks the tsx CLI's IPC socket, so the same tests were run through Node's supported loader.
• GitHub Actions run 36691127508 succeeded on exact head 97e2540f5179d1bf7dd785e5876edcf401b66d2e.
  • Ubuntu / Python 3.11: full suite succeeded (1,543 tests, 16 expected skips); original npm test, typecheck, build, and committed bundle verification succeeded.
  • Windows / Python 3.11: full suite succeeded (1,543 tests, 44 expected skips). All 7 native Windows process integration tests executed and passed with no skips.

No CI check is disabled or newly skipped.

Merged to main with approval as fa34141d79c4d4c1e2ac633f627b4515d1ac59a5. The merge tree matches the tested head exactly. Post-merge CI succeeded on both Ubuntu and Windows for that exact main commit.