Fix runtime attribution env signatures

[chubes4]

Summary

• Fixes Verify and fix Kimaki/OpenCode runtime signature attribution env vars #142.
• Removes the stale Kimaki runtime-signature registration because Kimaki 0.13 does not export KIMAKI_SESSION_ID, KIMAKI_THREAD_ID, or KIMAKI_THREAD_URL to OpenCode/tool subprocesses.
• Narrows the OpenCode runtime signature to the real exported OPENCODE_RUN_ID; source review and live smoke did not find OPENCODE_SESSION_ID.
• Documents upstream Kimaki follow-up for richer Discord attribution: Expose session/thread attribution env vars to OpenCode tool processes remorses/kimaki#137.
• Keeps runtime-specific names in wp-coding-agents, not Data Machine Code.

Verification

• ./tests/runtime-signature.sh
• for f in **/*.sh(.); do bash -n "$f" || exit 1; done
• homeboy test --path /Users/chubes/Developer/wp-coding-agents@fix-runtime-signature-env --extension wordpress reached plugin install/activation, then reported no PHPUnit files discovered for this repo.

Evidence

• Kimaki source review: cli/src/opencode.ts exports operational process env such as KIMAKI_DATA_DIR, KIMAKI_LOCK_PORT, KIMAKI_PARENT_LOCK_PORT, and KIMAKI_OPENCODE_PROCESS, not session/thread attribution vars.
• OpenCode source review: packages/opencode/src/util/opencode-process.ts defines and ensures OPENCODE_RUN_ID; source search found no OPENCODE_SESSION_ID.
• Live Kimaki/OpenCode tool env smoke showed OPENCODE_RUN_ID present and no OPENCODE_SESSION_ID/KIMAKI_SESSION_ID/KIMAKI_THREAD_ID/KIMAKI_THREAD_URL.

AI assistance

• AI assistance: Yes
• Tool(s): OpenCode (GPT-5.5)
• Used for: Source/runtime verification, patch drafting, tests, and PR preparation; Chris remains responsible for review and merge.

[chubes4]

Superseded by integration PR #162, which combines the Kimaki 0.13 cleanup work and resolves the overlapping bridge/test conflicts.