feat: bridge Kimaki context to Homeboy notifications

[chubes4]

Summary

• add an invocation-scoped OpenCode-to-wrapper boundary for Homeboy commands on managed Kimaki installs
• map validated Kimaki thread or channel snowflakes to generic Homeboy notification context without a guild ID or fallback route
• sync the managed plugin and wrapper through install/upgrade, and register the same Kimaki signature contract for DMC attribution
• cover package-upgrade survival, absent-attribution omission, and concurrent thread isolation in the managed Kimaki rig

Validation

• for test_file in tests/*.sh; do bash "$test_file"; done
• node tests/effective-prompt/run.mjs
• git diff --check
• bash -n bridges/kimaki.sh bridges/kimaki/homeboy-notification-context.sh bridges/kimaki/post-upgrade.sh runtimes/opencode.sh
• python3 -m py_compile lib/repair-opencode-json.py

Homeboy review audit ran, but its lint/test stages are unavailable because this component has no extension provider configured.

Closes #260.
Depends on remorses/kimaki#137.
Related to Extra-Chill/homeboy#7804.

AI disclosure

AI assistance: OpenCode using openai/gpt-5.6-terra.