fix: Prevent conflict resolution agent from destroying initiative branch

spawnConflictResolutionAgent was passing the initiative branch as branchName,
causing SimpleGitWorktreeManager.create() to force-reset it to the target
branch. Now spawns on a unique temp branch based off the initiative branch,
with the agent using git update-ref to advance the initiative branch after
resolving conflicts. Also fixes stale diff/commits cache after resolution.

apps/server/agent/prompts/conflict-resolution.ts

@@ -18,7 +18,7 @@ export function buildConflictResolutionPrompt(
   const conflictList = conflicts.map(f => `- \`${f}\``).join('\n');
 
   return `<role>
-You are a Conflict Resolution agent. Your job is to merge \`${targetBranch}\` into \`${sourceBranch}\` and resolve all merge conflicts so the initiative branch is up to date with the target branch.
+You are a Conflict Resolution agent. Your job is to merge \`${targetBranch}\` into the initiative branch \`${sourceBranch}\` and resolve all merge conflicts. You are working on a temporary branch created from \`${sourceBranch}\`. After resolving conflicts and committing, you must advance the initiative branch pointer using \`git update-ref\`.
 </role>
 
 <conflict_details>
@@ -52,13 +52,16 @@ Follow these steps in order:
 
 6. **Commit**: Stage resolved files with \`git add <file>\` (never \`git add .\`), then \`git commit --no-edit\` to complete the merge commit.
 
-7. **Signal done**: Write signal.json with status "done".
+7. **Update initiative branch**: Run \`git update-ref refs/heads/${sourceBranch} HEAD\` to advance the initiative branch to include the merge result. This is necessary because you are working on a temporary branch — this command propagates the merge commit to the actual initiative branch.
+
+8. **Signal done**: Write signal.json with status "done".
 </resolution_protocol>
 ${GIT_WORKFLOW}
 ${CONTEXT_MANAGEMENT}
 
 <important>
-- You are merging ${targetBranch} INTO ${sourceBranch} — bringing the initiative branch up to date, NOT the other way around.
+- You are on a temporary branch created from ${sourceBranch}. You are merging ${targetBranch} INTO this branch — bringing it up to date, NOT the other way around.
+- After committing the merge, you MUST run \`git update-ref refs/heads/${sourceBranch} HEAD\` to advance the initiative branch pointer. Without this step, the initiative branch will not reflect the merge.
 - Do NOT force-push or rebase. A merge commit is the correct approach.
 - If tests fail after resolution, fix the code — don't skip tests.
 - If a conflict is genuinely ambiguous (e.g., both sides rewrote the same function differently), signal "questions" with the specific ambiguity and your proposed resolution.

apps/server/trpc/routers/initiative.ts

@@ -459,7 +459,10 @@ export function initiativeProcedures(publicProcedure: ProcedureBuilder) {
           status: 'in_progress',
         });
 
-        // Spawn agent
+        // Spawn agent on a unique temp branch based off the initiative branch.
+        // Using initiative.branch directly as branchName would cause SimpleGitWorktreeManager.create()
+        // to run `git branch -f <branch> <base>`, force-resetting the initiative branch.
+        const tempBranch = `${initiative.branch}-conflict-${Date.now()}`;
         const prompt = buildConflictResolutionPrompt(initiative.branch, targetBranch, conflicts);
         return agentManager.spawn({
           name: `conflict-${Date.now()}`,
@@ -468,8 +471,8 @@ export function initiativeProcedures(publicProcedure: ProcedureBuilder) {
           mode: 'execute',
           provider: input.provider,
           initiativeId: input.initiativeId,
-          baseBranch: targetBranch,
-          branchName: initiative.branch,
+          baseBranch: initiative.branch,
+          branchName: tempBranch,
         });
       }),
   };

apps/web/src/components/review/InitiativeReview.tsx

@@ -68,8 +68,10 @@ export function InitiativeReview({ initiativeId, onCompleted }: InitiativeReview
     // When agent transitions from running/waiting to idle (completed)
     if (prev && ['running', 'waiting_for_input'].includes(prev) && conflictAgentStatus === 'idle') {
       void mergeabilityQuery.refetch();
+      void diffQuery.refetch();
+      void commitsQuery.refetch();
     }
-  }, [conflictAgentStatus, mergeabilityQuery]);
+  }, [conflictAgentStatus, mergeabilityQuery, diffQuery, commitsQuery]);
 
   // Preview state
   const projectsQuery = trpc.getInitiativeProjects.useQuery({ initiativeId });
@@ -266,7 +268,11 @@ export function InitiativeReview({ initiativeId, onCompleted }: InitiativeReview
         <ConflictResolutionPanel
           initiativeId={initiativeId}
           conflicts={mergeability.conflictFiles}
-          onResolved={() => mergeabilityQuery.refetch()}
+          onResolved={() => {
+            void mergeabilityQuery.refetch();
+            void diffQuery.refetch();
+            void commitsQuery.refetch();
+          }}
         />
       )}