docs: prepare ecosystem listings and launch packet

[hexsecs]

Why

Issue #484 tracks distribution work, but its body is truncated and does not provide a complete submission plan. Maintainers need accurate copy and concrete prerequisites before posting.

Changes

• Add a maintainer launch packet linked from release guidance and the docs navigation.
• Record the existing Awesome Vehicle Security listing and prepare an Awesome MCP Servers entry.
• Explain official MCP registry ownership verification and the required PyPI release step; current 0.9.2 lacks the marker.
• Provide Show HN and release announcement drafts, a version-pinned hardware-free demo, and Google/Bing sitemap submission instructions.
• Add the Unreleased changelog entry.

Refs #484. This PR does not close the issue: account verification, registry publication, and external submissions remain pending. No external outreach or release publication was performed.

Validation

• 1,638 tests passed, 1 skipped, 293 subtests passed.
• Published canarchy 0.9.2 demo executed successfully and emitted two synthetic frame events.
• Both live sitemap URLs returned HTTP 200 and valid XML (1 homepage URL; 41 docs URLs).
• Full strict docs build stalled during social-card/font processing. A separate strict content build disables the social plugin only in local configuration; full CI remains the merge gate.
• git diff --check passed.

Acceptance gates

1. Issue referenced in commit and PR.
2. Existing test suite passed; documentation-only change introduces no new behavior.
3. Changelog updated.
   4–5. No design or test specs changed.
4. No command surface, MCP implementation, or output schema changed; maintainer release guidance links the new workflow reference.
5. Existing listing and release facts checked; submission status stays on Reach: ecosystem listings and launch channels (awesome lists, MCP directories, Show HN, releases) #484.