docs: separate released and unreleased install paths

[Teingi]

Which issue or RFC does this PR close?

No linked issue. This fixes a user-reported onboarding failure.

Rationale for this change

The root README installed the released powercontext==0.1.0, then immediately recommended the unreleased powercontext service install command. It also configured integrations from the old v0.1.0 Git tag instead of the matching powercontext-v0.1.0 release tag. A user following those adjacent instructions therefore received No such command 'service' and could install an integration from a different code revision than the CLI and Server.

What changes are included in this PR?

• Separate released and unreleased installation paths in the English, Chinese, and Japanese root READMEs.
• Use the matching powercontext-v0.1.0 integration ref for the PyPI 0.1.0 package.
• Keep the native service commands within the unreleased master path where they are available.
• Keep powercontext server run as the copy-pasteable startup path for the released package.

Are there any user-facing changes?

Documentation now gives copy-pasteable, version-matched startup paths. There are no API, runtime, or persisted-data changes.

How was this change tested?

• make docs-test
• git diff --check upstream/master...HEAD
• Repository hooks for case conflicts, merge conflicts, end-of-file normalization, and trailing whitespace

The full hook command also ran ty check, which reported three unresolved scripts.scope_binding imports in unchanged upstream Codex plugin files. The exact upstream commit (259bee3a) has successful quality, check-docs, test-matrix, and integration check runs.

AI usage statement

OpenAI Codex (GPT-5) assisted with diagnosis, documentation edits, and validation.

[PsiACE]

lgtm