fix: avoid proposal identity collisions in multi-repo mode

web/src/components/ProposalList.test.tsx

@@ -1,4 +1,4 @@
-import { render, screen, fireEvent } from '@testing-library/react';
+import { render, screen, fireEvent, within } from '@testing-library/react';
 import { describe, it, expect } from 'vitest';
 import { ProposalList } from './ProposalList';
 import type { Proposal, PullRequest } from '../types/activity';
@@ -407,4 +407,77 @@ describe('ProposalList', () => {
       screen.queryByText(/Same number issue comment/i)
     ).not.toBeInTheDocument();
   });
+
+  it('keeps selection scoped by repo when proposal numbers collide', () => {
+    const proposals: Proposal[] = [
+      {
+        number: 42,
+        title: 'Colony proposal',
+        phase: 'discussion',
+        author: 'worker',
+        createdAt: '2026-02-05T09:00:00Z',
+        commentCount: 1,
+        repo: 'hivemoot/colony',
+      },
+      {
+        number: 42,
+        title: 'Governance proposal',
+        phase: 'discussion',
+        author: 'scout',
+        createdAt: '2026-02-05T10:00:00Z',
+        commentCount: 1,
+        repo: 'hivemoot/hivemoot',
+      },
+    ];
+    const comments = [
+      {
+        id: 2001,
+        issueOrPrNumber: 42,
+        type: 'proposal' as const,
+        repo: 'hivemoot/colony',
+        author: 'worker',
+        body: 'Colony-specific thread',
+        createdAt: '2026-02-05T11:00:00Z',
+        url: 'https://github.com/hivemoot/colony/issues/42#issuecomment-2001',
+      },
+      {
+        id: 2002,
+        issueOrPrNumber: 42,
+        type: 'proposal' as const,
+        repo: 'hivemoot/hivemoot',
+        author: 'queen',
+        body: 'Governance-specific thread',
+        createdAt: '2026-02-05T12:00:00Z',
+        url: 'https://github.com/hivemoot/hivemoot/issues/42#issuecomment-2002',
+      },
+    ];
+
+    render(
+      <ProposalList
+        proposals={proposals}
+        comments={comments}
+        repoUrl={repoUrl}
+      />
+    );
+
+    const colonyCard = screen.getByText('Colony proposal').closest('article');
+    expect(colonyCard).not.toBeNull();
+    fireEvent.click(within(colonyCard as HTMLElement).getByRole('button'));
+
+    expect(screen.getByText('Colony-specific thread')).toBeInTheDocument();
+    expect(
+      screen.queryByText('Governance-specific thread')
+    ).not.toBeInTheDocument();
+
+    const governanceCard = screen
+      .getByText('Governance proposal')
+      .closest('article');
+    expect(governanceCard).not.toBeNull();
+    fireEvent.click(within(governanceCard as HTMLElement).getByRole('button'));
+
+    expect(screen.getByText('Governance-specific thread')).toBeInTheDocument();
+    expect(
+      screen.queryByText('Colony-specific thread')
+    ).not.toBeInTheDocument();
+  });
 });

web/src/components/ProposalList.tsx

@@ -19,13 +19,20 @@ export function ProposalList({
   repoUrl,
   filteredAgent,
 }: ProposalListProps): React.ReactElement {
-  const [selectedProposalNumber, setSelectedProposalNumber] = useState<
-    number | null
-  >(null);
+  const [selectedProposalKey, setSelectedProposalKey] = useState<string | null>(
+    null
+  );
+
+  const getProposalKey = (proposal: Proposal): string =>
+    `${proposal.repo ?? 'unknown'}:${proposal.number}`;
+
+  const getExplorerId = (proposal: Proposal): string =>
+    `decision-explorer-${getProposalKey(proposal).replace(/[^a-zA-Z0-9_-]/g, '-')}`;
 
   const selectedProposal = useMemo(
-    () => proposals.find((p) => p.number === selectedProposalNumber) ?? null,
-    [proposals, selectedProposalNumber]
+    () =>
+      proposals.find((p) => getProposalKey(p) === selectedProposalKey) ?? null,
+    [proposals, selectedProposalKey]
   );
 
   const snapshot = useMemo(
@@ -72,11 +79,12 @@ export function ProposalList({
     <div className="space-y-4">
       <div className="grid gap-4 sm:grid-cols-2">
         {proposals.map((proposal) => {
-          const isSelected = proposal.number === selectedProposalNumber;
+          const proposalKey = getProposalKey(proposal);
+          const isSelected = proposalKey === selectedProposalKey;
 
           return (
             <article
-              key={proposal.number}
+              key={proposalKey}
               className={`bg-white/40 dark:bg-neutral-800/40 border rounded-lg motion-safe:transition-colors ${
                 isSelected
                   ? 'border-amber-400 dark:border-amber-500'
@@ -86,10 +94,10 @@ export function ProposalList({
               <button
                 type="button"
                 onClick={() =>
-                  setSelectedProposalNumber(isSelected ? null : proposal.number)
+                  setSelectedProposalKey(isSelected ? null : proposalKey)
                 }
                 aria-expanded={isSelected}
-                aria-controls={`decision-explorer-${proposal.number}`}
+                aria-controls={getExplorerId(proposal)}
                 className="w-full text-left p-4 hover:bg-white/60 dark:hover:bg-neutral-800/60 rounded-lg focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-amber-500 focus-visible:ring-offset-1 dark:focus-visible:ring-offset-neutral-800"
               >
                 <div className="flex justify-between items-start mb-2">
@@ -180,7 +188,7 @@ export function ProposalList({
 
       {selectedProposal && snapshot && (
         <section
-          id={`decision-explorer-${selectedProposal.number}`}
+          id={getExplorerId(selectedProposal)}
           aria-label={`Decision explorer for proposal #${selectedProposal.number}`}
           className="bg-white/40 dark:bg-neutral-800/40 border border-amber-300 dark:border-neutral-600 rounded-lg p-4"
         >