Paginate Code Scanning alerts instead of returning only the first page

[Tarasusrus]

What this PR does

Fixes #773.

GetCodeScanningAlerts made a single ListAlertsForRepo / ListAlertsForOrg call with no pagination loop and no PerPage override, so GitHub's default page size of 30 applied. Any repository or organization with more than 30 code scanning alerts silently returned only the first 30, regardless of the true count.

Fix

Loop over pages using resp.NextPage with PerPage: 100, the same idiom already used by the other paginated queries (e.g. GetAllDeployments in deployments.go). ListOptions is referenced explicitly because AlertListOptions also embeds ListCursorOptions, which would make a bare Page/PerPage ambiguous.

Tests

Extended the code scanning mock client to serve successive pages and added TestGetCodeScanningAlertsPagination:

• repository query walks 3 pages (3 + 3 + 2 alerts) and returns all 8, requesting pages 1, 2, 3 in order.
• organization query walks 2 pages and returns all 4.

Existing single-page tests continue to pass. go test ./pkg/... is green.

[cla-assistant]

All committers have signed the CLA.

[cla-assistant]

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[cla-assistant]

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[mattvella07]

LGTM

[mattvella07]

@Tarasusrus Please sign the CLA

[mattvella07]

@Tarasusrus Let me know once you sign the CLA so I can make sure that the license/cla check is working

[Tarasusrus]

@mattvella07 Signed — license/cla is now green here and on #778.

The only remaining red check is Add issue to project, which fails only on fork PRs: #777 and #778 fail, while #776, #779, #780 and #782 — all branches in this repo — pass. It dies in create-github-app-token with Unable to get ACTIONS_ID_TOKEN_REQUEST_URL, i.e. the OIDC token isn't exposed to workflows triggered from a fork, so it can't mint the app token. Unrelated to this change, but it does mean the job can never go green on an outside contribution.

Everything else — build, docs, and the full Playwright E2E matrix — is green. Ready to merge from my side. Thanks for the review!

[mattvella07]

@Tarasusrus Thanks! That check is to help us keep track of PRs, so its not required to pass. I'll go head and merge. Thanks for the contribution!