Prepare v0.2.0 Developer Preview candidate

[jacklv-coder]

Summary

• prepare the v0.2.0 Developer Preview source candidate and align package/example version metadata
• record the completed Jack iPhone physical-device core-flow evidence
• add bilingual release notes, testing guidance, readiness metadata, SPDX SBOM, checksums, and reproducible compliance artifacts
• teach the source-release verifier and CI to audit an explicitly blocked candidate without weakening the strict release gate

Release boundary

This PR does not publish v0.2.0.

• no tag or GitHub Release is created
• explicit source-release authorization remains false
• runtime and RootFS redistribution remain blocked
• the audited source archive contains neither RootFS nor runtime binary artifacts
• public consumers should continue pinning v0.1.0

A separate explicit authorization and passing strict release audit are required before any v0.2.0 source release. Runtime/RootFS distribution additionally requires its own completed redistribution evidence and approval.

Physical-device evidence

Validated on Jack iPhone (iPhone 14 Pro, iOS 26.6) with Xcode 26.6:

• embedded RootFS exact size and SHA-256 verification
• default 90 x 2-second stability smoke; all 20 health checks passed
• 90 persistent PTY and Files cycles
• exact 576 KiB delimited zero-byte output
• output-limit recovery
• Files preview and shutdown
• 0.0 MiB post-warm footprint growth
• 83.2 MiB lifecycle peak under the 256 MiB budget
• smoke app removed after validation

Validation

• Codex CR: no actionable defects after resolving the first review's two P2 documentation/compliance issues
• swift test: 200 tests, 1 expected skip, 0 failures
• source release verification tests: 15 runs / 48 assertions
• release compliance tests: 70 runs / 533 assertions
• documentation check: 22 Chinese primaries and 22 English mirrors
• generated compliance artifacts are reproducible
• candidate source archive audit: 347 entries, 260 regular files, source track blocked, RootFS absent, runtime artifacts absent