feat: add comment update and comment delete

[seraph-pixelperfect]

Closes #27
Depends on #47

What

• comment update <COMMENT-ID> --body "..."|--body-file <path> — edits a comment's body via the commentUpdate mutation. Body guards (mutual exclusion, readBodyFile, required-field errors) mirror the create path exactly. A missing comment fails loud with NOT_FOUND (update is not idempotent-by-convention — only delete is).
• comment delete <COMMENT-ID> — removes a comment via commentDelete. Idempotent no-op when the comment is already gone, mirroring deleteIssueCmd's pre-fetch pattern: comment(id:) returns null → comment: "<id>" not found (no-op), no mutation issued. Like issue delete, any missing id no-ops.
• comment list surfaces comment ids — every row now leads with the comment's full UUID (first column, comments[n]{id,author,body,created}), the handle update/delete target. The query already selected id (COMMENT_LIST_FIELDS); only the render changed. A hint advertises both new subcommands.
• COMMENT_HELP documents the new subcommands and the now-reserved words (list, update, delete); a bare ref still routes to create (backward compat, tested). Skill prose updated; SKILL.md regenerated via pnpm run build:skill.

Schema source (verified against @linear/sdk v90.0.0 generated documents, npm pack @linear/sdk → dist/index-zxW4m1xd.d.mts)

• UpdateCommentMutationVariables (line 61303): commentUpdate(id: String!, input: CommentUpdateInput, skipEditedAt?) → CommentPayload { comment, lastSyncId, success }.
• CommentUpdateInput (line 3220): exactly one non-internal field — body: String ("The comment content"); everything else is [Internal]. Hence no omit-null input builder: body is the single required value.
• DeleteCommentMutationVariables (line 61264): commentDelete(id: String!) → DeletePayload { entityId, lastSyncId, success } (line 5164) — success is all the CLI needs, mirroring issueDelete.
• Root comment(id:) query exists (QueryCommentArgs line 20047: { hash?, id? }, returns Maybe<Comment>; missing id → null, not an error) — used by the pre-fetch. It also carries issue { identifier } (Comment.issue, nullable: "Null if the comment belongs to a different parent entity type") for the confirmations.

Demo (real code paths, stubbed network — captured via a fetch-stub harness)

=== 1. comment list LIN-1 (ids now surfaced, first column) ===        [BEFORE: rows were {author,body,created}, no id]
count: 1
comments[1]{id,author,body,created}:
  6f1b2f3a-1111-4bbb-9ccc-000000000001,Ada,Stale body text,1d ago
help[2]:
  Run `linear-axi comment LIN-1 --body "..."` to reply
  Run `linear-axi comment update <id> --body "..."` to edit, or `comment delete <id>` to remove
  doc 1: query Issue($id: String!) { issue(id: $id) { ... } }
         vars: {"id":"LIN-1"}
  doc 2: query Comments($issueId: ID!, $first: Int!, ...) { comments(filter: { issue: { id: { eq: $issueId } } }, ...)
         vars: {"issueId":"ir-1","first":50}

=== 2. comment update <id> --body "..." ===
comment: updated on LIN-1
help[2]:
  Run `linear-axi comment list LIN-1` to read the thread
  Run `linear-axi comment delete 6f1b2f3a-1111-4bbb-9ccc-000000000001` to remove it
  doc 1: query Comment($id: String!) { comment(id: $id) { id issue { identifier } } }
         vars: {"id":"6f1b2f3a-1111-4bbb-9ccc-000000000001"}
  doc 2: mutation UpdateComment($id: String!, $body: String!) { commentUpdate(id: $id, input: { body: $body }) { success } }
         vars: {"id":"6f1b2f3a-1111-4bbb-9ccc-000000000001","body":"Edited: fixed the typo, see notes"}

=== 3. comment delete <id> ===
deleted: comment on LIN-1
  doc 1: query Comment($id: String!) { comment(id: $id) { id issue { identifier } } }
  doc 2: mutation DeleteComment($id: String!) { commentDelete(id: $id) { success } }
         vars: {"id":"6f1b2f3a-1111-4bbb-9ccc-000000000001"}

=== 4. comment delete <same id> again (idempotent no-op) ===
comment: "6f1b2f3a-1111-4bbb-9ccc-000000000001" not found (no-op)
  doc 1: query Comment($id: String!) { comment(id: $id) { id issue { identifier } } }   <- pre-fetch null, no mutation issued

Local gates (real output)

$ pnpm build            → tsc, clean
$ pnpm lint             → eslint ., clean
$ pnpm run build:skill -- --check
skills/linear-axi/SKILL.md is up to date.
$ pnpm test
 Test Files  18 passed (18)
      Tests  214 passed (214)          <- was 200 in 17 files on the base; +14 in test/comment-update-delete.test.ts, +1 header assertion updated in comment-list.test.ts
$ pnpm run format:check → RED, pre-existing: the same 18 files as the base branch (verified set-identical via stash/diff); the new test file passes `prettier --check`.

New tests cover: update document + variables; --body-file content as body; mutual exclusion (zero network); update not-found loud NOT_FOUND; no-issue fallback render; delete document; delete idempotent no-op (pre-fetch null → no mutation); missing id / unknown-flag rejection on both paths; list document + render carrying ids; bare-ref dispatch to create; help contents; and the full list → update → delete round trip asserting all six documents in sequence.

Stacked PR note

Stacked on #47 (stack: #37→#38→#39→#40→#41→#42→#43→#44→#45→#46→#47). No CI checks appear here — ci.yml only triggers on PRs targeting main. CI runs when retargeted to main after the stack merges; local gates above are the evidence. Not retargeting.

CI quota-block caveat: if checks do appear and look failed, billing/spending-limit rejections resemble check failures — check gh run view <run-id> / the jobs API for a billing annotation or empty steps with ~3-4s duration. If quota-blocked, this PR relies on the local output above; no retries.

Judgment calls / ambiguities flagged

• Delete no-op via pre-fetch vs error-mapping: chose the pre-fetch (comment(id:) → null ⇒ no-op, no mutation), for consistency with deleteIssueCmd's established pattern; it also yields the issue identifier for the confirmation. Same asymmetry as issues: any missing id no-ops on delete, while update is loud.
• Id rendering in list: rendered complete, never truncated — a truncated UUID could not be copy-pasted into comment update/delete. Cost: +36 chars/row.
• Update confirmation shape: comment: updated on LIN-1 (mirrors comment: added to LIN-1), falling back to comment: updated <id> when the comment has no parent issue (Comment.issue is nullable). Kept minimal rather than echoing the new body.

Identity

Automated agent dispatch authenticated as seraph-pixelperfect, submitted for human review — not self-approved. Merge is a human decision.

[ghostinprod-pixelperfect]

Superseded by merged rc/0.2 PR #52 (commit ad6b141), which consolidated this write/transport stack with validation and review fixes.