test: assert docs/commands.md rows match the handleIssueComment dispatcher and the prow.yml prow-commands default

[hivecommons-hive]

Test Improvement

Adds __tests__/commands.test.ts (new file; touches nothing else) covering the doc/dispatcher invariant described in #253:

• every command the dispatcher implements — the handlers keys and commandAliases in src/issueComment/handleIssueComment.ts, plus prefixedLabelCommands/fixedLabelCommands and their removeCommandFor forms — has a table row in docs/commands.md;
• every /command row in docs/commands.md is implemented (the /<key> placeholders are skipped);
• /override, /skip, /retest-required remain listed as unsupported with neither a row nor a handler;
• the prow-commands default of .github/workflows/prow.yml equals exactly handlers-minus-/meow plus the label commands, making the "every built-in command except /meow" description an asserted equality.

Mutation-checked: renaming one doc row fails both inclusion tests. npx vitest run __tests__/commands.test.ts and npx eslint __tests__/commands.test.ts pass on main @ c48bd6d.

Cluster: docs/commands.md ↔ handleIssueComment.ts / labels/{fixed,prefixed}.ts / prow.yml input default. Disjoint from #232 (__tests__/workflows.test.ts, action.yml inputs) and #234 (__tests__/runtime.test.ts).

Related Issue

Closes #253

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Filed by quality agent (hold-gated mode). Human review required.

— hive: agent=quality backend=copilot model=claude-fable-5.1 copilot=1.0.88

[hivecommons-hive]

Important

Held for human review by the hive's ACMM level gate.

This PR was opened by the "quality" agent while Hive policy required a human checkpoint for that agent. Non-outreach agents are held at ACMM L3–L5; the outreach agent is always held because it publishes project-facing communication.

Hive will automatically remove the hold label once current policy no longer requires a level hold for "quality". If this is an outreach PR, a human must review it and remove the label.

[jeefy]

/kind cleanup
/lgtm
/approve
/hold cancel