chore(codex): close llms feed cache ops ledger

[fermatmind]

What changed

• Closed the PR-train ledger for FAP-WEB-LLMS-FEED-CACHE-OPS-01 after PR FAP-WEB-LLMS-FEED-CACHE-OPS-01: add llms feed cache-only ops workflow #1720 merged.
• Recorded merge commit, merged timestamp, remote branch deletion, local cleanup, and post-merge revalidation facts.

Why

• Repository rules require PR-train items to close their state as merged after merge. Because main is protected, this is a ledger-only follow-up with no new train id.

Validation

• ruby -e 'require "yaml"; require "json"; YAML.load_file("docs/codex/pr-train.yaml"); JSON.parse(File.read("docs/codex/pr-train-state.json")); puts "parse ok"'
• git diff --check
• Changed-file scope validation limited to docs/codex train metadata.

Deferred items

• No workflow dispatch, PM2 reload, deployment, CMS/backend write, llms eligibility change, Search Queue write, IndexNow call, or HMAC revalidation API change occurred.