master CI is broken: markdownlint fails on every push since #230

[VasilevNStas]

Problem

Every push to master fails the markdown-lint workflow with 10 errors:

Line	Rule	Message
18	MD040	Fenced code blocks should have a language (```)
44	MD029	Ordered list item prefix (Expected: 1; Actual: 2)
59	MD029	Ordered list item prefix (Expected: 1; Actual: 3)
77	MD029	Ordered list item prefix (Expected: 1; Actual: 4)
83	MD029	Ordered list item prefix (Expected: 1; Actual: 5)
94	MD060	Table column style (missing spaces around pipes)
97	MD013	Line length (Expected: 80; Actual: 89)

First seen on the merge commit of #230 (June 13), reproduced on every subsequent push to master.

Root cause

The markdown-lint workflow only runs on push to master, not on pull_request. The errors were never caught before merge. See .github/workflows/markdown-lint.yml — it triggers on push: branches: [master] but has no pull_request trigger.

This means a PR with a broken README can pass all checks and break master on merge.

How to fix

Option A (short-term): Merge a PR that fixes README.md

PRs #273, #274, #275, #276, #277, #278, #279, #280, #281, #282 all include the same README.md fixes. Merging any one will restore green CI on master. All 10 pass CI.

Option B (long-term): Add pull_request trigger to markdown-lint workflow

Change the workflow to also run on pull_request (similar to what #240 did for this same workflow). This catches markdownlint issues before merge, not after.

 on:
   push:
     branches: [master]
+  pull_request:
+    branches: [master]

---

Note: These 10 PRs also add wall-clock timeout, SIGTERM handling, configurable max-cycles, portable readlink, version diagnostics, heartbeat, and more — all independently reviewed and CI-green.

[VasilevNStas]

Update: The markdown-lint workflow already has the pull_request trigger (added by #240, merged before #230). The 10 errors in README.md were introduced by #230 and should have been caught but slipped through. Our PRs #273-#282 all fix these errors as part of their changes.

[VasilevNStas]

@yegor256 plz review