feat(integrations): Create ExternalActor from public GH email opportunistically

[hobzcalvin]

Add CommitAuthor.public_email_queried_at to track if/when we've checked a given author's GH profile for a public email address.

For CommitAuthors pushing new commits (whether they're new or old), if we haven't checked their GH profile in the past 30 days, check and create an ExternalActor mapping if their public email maps to a Sentry user in the given org.

[github-actions]

This PR has a migration; here is the generated SQL for src/sentry/migrations/1105_commitauthor_public_email_queried_at.py

for 1105_commitauthor_public_email_queried_at in sentry

--
-- Add field public_email_queried_at to commitauthor
--
ALTER TABLE "sentry_commitauthor" ADD COLUMN "public_email_queried_at" timestamp with time zone NULL;

[wedamija]

Does it make sense to give this a hardcoded default date (maybe Jan 01, 2026) so that we can mark this column as not null? It will be overwritten once we start performing these checks, so might be worthwhile to avoid a null

[hobzcalvin]

I'd say sure, but I think the cost of backfilling a default for 5411672 rows (yikes!) makes it not worth it. There may be many rows where we never set this--I think a LOT of CommitAuthors are extremely old and no longer generating commits we care about, so they'll never be checked.

[wedamija]

I guess it depends if we care if the older rows just have the sentinel value forever. We don't really need to perform the backfill if we just set a static default for existing rows

[wedamija]

lgtm, I'll leave it up to you about whether you want to try and make the column not-nullable

[cursor]

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

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[github-actions]

This PR has a migration; here is the generated SQL for src/sentry/migrations/1107_commitauthor_public_email_queried_at.py

for 1107_commitauthor_public_email_queried_at in sentry

--
-- Add field public_email_queried_at to commitauthor
--
ALTER TABLE "sentry_commitauthor" ADD COLUMN "public_email_queried_at" timestamp with time zone NULL;