docs: sync v0.3 public truth guards

[CoderDeltaLAN]

Summary

• Sync product strategy wording with the published v0.3.0 GitHub Release and PyPI package line.
• Sync SUPPORT.md with manually verified private vulnerability reporting status.
• Extend the local post-release audit to catch stale v0.2 public-truth wording and stale private vulnerability reporting claims.

Checks

• Local check suite passed: 142 tests, Ruff, text hygiene, git whitespace.
• Local post-release audit passed.
• Pre-push guard passed against commit ede3550.

Boundaries

• Documentation and audit-guard change only.
• No runtime code changes.
• No release, tag, PyPI, branch protection, or workflow behavior changes.