chore(release): prepare v1.3.0

[hidb4ai]

Which issue or RFC does this PR close?

Release preparation for v1.3.0; no issue is closed.

Rationale for this change

Prepare consistent installation references, generated API contracts, and bilingual website release notes for PowerContext 1.3.0.

What changes are included in this PR?

• Synchronize the OpenAPI version, English/Chinese/Japanese READMEs, bilingual installation and quickstart guides, and DSH installation references to 1.3.0 using make version-bump VERSION=1.3.0.
• Regenerate Python API metadata, the Dify contract version, and Desktop contract digests, and update the API version assertions, including the durable Server identity test.
• Add English and Chinese website release notes highlighting Atomic Memory and decision-model Memory write governance (feat(runtime): add decision policy governance types #1921), alongside the unsigned Windows Desktop preview (feat(desktop): add scoped memory workflow preview #1663), Dashboard search visibility (feat(dashboard): expose Memory search modes and channels #1878) and optional local authentication (feat(config): make local dashboard authentication optional #1707), Artifact merge/restoration and search, Server discovery and diagnostics, Agent integrations, extraction/recall fixes, evaluation, and migration limits. Preserve earlier release entries.
• Document the offline Atomic Memory migration required for existing collection databases in both installation guides.

Are there any user-facing changes?

Installation commands and website release notes target 1.3.0. The upgrade guidance requires database backup and offline Atomic Memory migration before starting the new service against existing collection databases. The limited unified migration bundle is not a complete Server upgrade path.

Decision-model write governance is opt-in and defaults to shadow/no_external_call when enabled. Raw-content assessment requires local_only and a loopback backend; enforcing promotion still requires calibration and evaluation. Scope-isolated durable observations exclude candidate and evidence text.

This PR updates release metadata and documentation; package versions remain derived from the powercontext-v1.3.0 Git tag.

How was this change tested?

• make version-bump VERSION=1.3.0
• make release-check VERSION=1.3.0
• make contract-test — 51 passed
• uv run pytest tests/test_release_version.py -q — 12 passed
• pnpm --dir desktop generate and pnpm --dir desktop generate:check
• pnpm --dir website lint
• pnpm --dir website test — 4 test files passed
• make dify-test — plugin: 64 passed, 16 skipped; HTTP/SQLite: 2 passed, 1 skipped (real Dify host checks not configured)
• uv run pytest tests/test_server.py -q — 58 passed
• git diff --check

Website release checks and tests used the repository-required Node.js 24.14.1. Full application/backend acceptance and the production website build were not run for this metadata/documentation change.

AI usage statement

Prepared with OpenAI Codex, including version synchronization, release-note drafting, generated contract updates, and validation.

[CLAassistant]

All committers have signed the CLA.