chore(release): prepare v1.0.0

[Teingi]

Which issue or RFC does this PR close?

Related: #1555. No issue or RFC is closed.

Rationale for this change

Prepare the stable PowerContext 1.0.0 release. Installation instructions and API metadata now use version 1.0.0, with Agent integrations pinned to powercontext-v1.0.0.

What changes are included in this PR?

• Update the English, Chinese, and Japanese READMEs, bilingual installation guides, and DSH plugin installation example.
• Set the canonical OpenAPI version to 1.0.0 and regenerate the Python API metadata.
• Add bilingual 1.0.0 release notes covering guided setup, Topic Memory, Profiles, reviewed Dream workflows, integrations, and upgrade considerations.
• Update release workflow examples and cover stable-version matching in the configuration wizard test. Package versioning continues to derive from Git tags.

Are there any user-facing changes?

The documentation installs the stable release and matching plugins. Upgrade guidance covers database backups, coordinated Server/client/integration upgrades, Dashboard authentication, and explicit consent for remote plaintext HTTP. Windows remains experimental. This PR changes release metadata and documentation; it does not introduce runtime or database schema changes.

How was this change tested?

• make api-generate and make contract-test: generated artifacts verified; 47 contract tests passed.
• make check: integration manifest checks, lock consistency, all pre-commit hooks, and type checks passed.
• make docs-test with Node 24.14.1: lint, build, and export validation passed for 792 public pages; both 1.0.0 release pages contain the expected install command and release link.
• Configuration CLI and release-verification tests: 63 passed. Fresh-database release smoke: 1 passed after rerunning outside the socket-restricted sandbox.
• Built wheel and sdist from a disposable repository tagged powercontext-v1.0.0; both passed twine check.
• Installed the wheel in a fresh virtual environment and verified CLI, Server, MCP, and SQLite Memory search. Installed package and API versions both equal 1.0.0.

AI usage statement

Prepared with OpenAI Codex (GPT-6), including release documentation, API metadata generation, and validation.

[frf12]

LGTM