feat: add create-kafka-topic skill

[evanh]

Adds a create-kafka-topic skill that provisions a new Kafka topic across the four repos that must all agree for a Sentry topic to exist and deploy:

• sentry-kafka-schemas — schema definition + CODEOWNERS entry
• ops — default partitions, per-region overrides, all_topics.yaml, schemas requirement bump
• sentry — Topic enum + KAFKA_TOPIC_TO_CLUSTER, schemas dependency bump
• getsentry — cell-silo topic→cluster mapping

It opens one PR per repo and reports the four PR links annotated with their merge-order dependencies (the schemas PR must merge + release before the ops/sentry version bumps).

The steps and file formats were reconciled against the real taskworker-ingest-push topic PRs (sentry-kafka-schemas#484, ops#20917, sentry#117135, getsentry#20495). Per how ops works, CI regenerates the materialized/k8s config (make materialize), so the skill only edits source-of-truth files.

Includes the required SPEC.md and registration in README.md, .claude/settings.json, and the claude-settings-audit allowlist.

🤖 Generated with Claude Code

[cursor]

Cursor Bugbot has reviewed your changes and found 1 potential issue.

There are 4 total unresolved issues (including 3 from previous reviews).

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[linear-code]

STREAM-1224

[evanh]

Addressed the review comments in 6daf901:

• Enabled regions omit override files (Bugbot) — fixed. The "file set" is now explicitly the sibling-derived candidate set ∪ every region the user enabled, so an enabled region always gets an override file even if the sibling topic didn't define it.
• Ambiguous / missing regional-override path (Bugbot + Sentry) — fixed. Step 3.2 now uses the full shared_config/kafka/topics/regional_overrides/<region>/<topic_name>.yaml path, matching git add shared_config/kafka/topics/.
• Enum template conflates names (Bugbot) — fixed. Clarified the Topic member is SCREAMING_SNAKE_CASE (hyphens→underscores, uppercased) while the value is the kebab-case name, with a concrete TASKWORKER_LAUNCHPAD_PUSH = "taskworker-launchpad-push" example.
• Hardcoded default cluster mapping (Bugbot) — not a current bug: all 97 KAFKA_TOPIC_TO_CLUSTER entries map to "default". Softened the wording anyway to say match a sibling's value if a family ever uses a non-default cluster.

[untitaker]

i think the skill should ask a few clarifying questions about whether this really needs a schema change. if this is just another taskbroker or outcomes topic then a few steps can be skipped

[evanh]

i think the skill should ask a few clarifying questions about whether this really needs a schema change. if this is just another taskbroker or outcomes topic then a few steps can be skipped

Which steps can be skipped?

[untitaker]

see getsentry/sentry-kafka-schemas#490 (review) -- this is not how we create taskworker or outcomes topics. we already have a schema definition for those, and sentry-kafka-schemas should not contain infra-specific topics that are not present in self-hosted or elsewhere

EDIT: after discussing in slack we did create taskworker topics like that. I do think we should still add a caveat about outcomes