feat(inbox): suppress dialog with dismissal feedback

[Twixes]

Summary

• Replaces the bulk-suppress confirmation in the inbox toolbar — and adds a new Suppress button to the top of the report detail pane — with a dialog that captures why a report is being suppressed.
• The dialog has six radio options ("Already fixed elsewhere", "Agent's analysis is wrong", "Won't fix - intentional behavior", "Won't fix - issue is real but irrelevant", "I'm not the right reviewer", "Other") plus an optional free-form add detail textarea.
• Suppression continues to flow through the existing POST /api/projects/:team_id/signals/reports/:id/state/ endpoint, with two new optional body fields (dismissal_reason, dismissal_note). The backend persists those as a new dismissal-type SignalReportArtefact so the rationale survives status changes and stacks across multiple dismissals. The companion backend PR is in PostHog/posthog.

Notable changes

• New SuppressDialog component (apps/code/src/renderer/features/inbox/components/SuppressDialog.tsx) — uses Radix Dialog + RadioGroup + TextArea.
• useInboxBulkActions.suppressSelected(dismissal?) now takes an optional { reason, note } payload.
• posthogClient.updateSignalReportState accepts and forwards dismissal_reason / dismissal_note.
• DismissalArtefact shared type + parser branch in the artefact normalizer.
• Suppress button on the report detail header closes the pane on success.

Test plan

• Bulk-select reports in the inbox, click Suppress, pick a reason, optionally add detail, confirm — reports become suppressed and the dismissal artefact appears in the artefacts list.
• Open a single report in the detail pane, click Suppress in the header, confirm with no note — succeeds and pane closes.
• Try to confirm without picking a reason — button is disabled with a "you haven't picked a reason" tooltip.
• Verify the existing Snooze / Delete flows are unaffected (Delete still uses the original `AlertDialog`).
• Confirm typecheck and biome pass.

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Created with PostHog Code