docs: prepare 0.2.30 changelog

[shakkernerd]

Summary

• restore the missing 0.2.29 changelog from the tagged release range
• document the user-facing OpenClaw compatibility, upgrade recovery, runtime safety, and snapshot consistency work for 0.2.30

Verification

• git diff --check
• compared v0.2.28..v0.2.29 and v0.2.29..a88a4b4 against their merged pull requests and tagged commits

[shakkernerd]

Merged using squash.

What changed after review:

• Restored the missing 0.2.29 history from the tagged release range.
• Added 0.2.30 notes covering merged PRs #40 through #57.
• Kept the change documentation-only; runtime and release-script behavior are unchanged.

Verification:

• Refreshed against current origin/main before merging.
• AWS Crabbox cbx_acddb956ce9d: full Linux Rust 1.88 suite, Windows cross-check, package/install flows, historical OpenClaw upgrades, rollback, and current-stable runtime smoke passed.
• Real macOS: full suite, ARM64/Intel package checks, installer, historical upgrades, rollback, and current-stable runtime smoke passed.
• Auto-review: not applicable to the documentation-only diff; entries were checked against tagged ranges and merged PRs.
• GitHub checks: Format, Rust 1.88 minimum, Windows compile, Ubuntu tests, and macOS tests passed.

Landed on main:

• Final landed SHA: 60407a3; range a88a4b4...60407a3.

Thanks @shakkernerd!