feat(commands): register review/pause/resume/resolve/configuration/explain in the @gittensory action-command registry + parser

[JSONbored]

The @gittensory PR-comment parser currently recognizes exactly ONE action command: GITTENSORY_ACTION_COMMANDS = ["gate-override"] (src/github/commands.ts:58). Every other verb collapses to the "help" card. This is the foundation bounty for #1960: extend the action-command registry + parseGittensoryMentionCommand so the new verbs are recognized as first-class action commands (not silently downgraded to help), capturing the trailing argument (e.g. the finding id for explain, a reason for pause). PURE parsing only — no dispatch, no side effects, no auth. This unblocks every per-command bounty below.

Deliverables

• Add "review","re-review","pause","resume","resolve","configuration","explain" to GITTENSORY_ACTION_COMMANDS in src/github/commands.ts:58 (keep "gate-override")
• Extend parseGittensoryMentionCommand (src/github/commands.ts:164) so each new verb returns {name, raw, reason/argument} via the existing ACTION_COMMANDS branch; alias "re-review"→"review" so both spellings resolve to one canonical name
• Preserve the existing behavior: an unknown verb still resolves to "help", and a bare @gittensory with no verb still resolves to "help"
• Capture the free-text tail (match[2]) as argument/reason for verbs that take one (explain , pause )
• Unit tests in test/unit/github-commands.test.ts covering EACH new verb + the re-review alias + trailing-arg capture + the unknown-verb→help fallback + bare-mention fallback (both sides of every branch for 97% branch coverage)

References

• src/github/commands.ts:23 (PUBLIC_MENTION_COMMAND_CATALOG)
• src/github/commands.ts:58 (GITTENSORY_ACTION_COMMANDS)
• src/github/commands.ts:164 (parseGittensoryMentionCommand)
• test/unit/github-commands.test.ts
• #1960

Part of #1960.

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size: S · held for later release (gittensor:feature once activated)

[linear-code]

JSO-2261