feat: Allow editing review comments

Add update method to ReviewCommentRepository, updateReviewComment tRPC
procedure, and inline edit UI in CommentThread. Edit button appears on
user-authored comments (not agent comments) when unresolved. Uses the
existing CommentForm with a new initialValue prop.

apps/server/trpc/routers/phase.ts

@@ -346,6 +346,20 @@ export function phaseProcedures(publicProcedure: ProcedureBuilder) {
         return repo.create(input);
       }),
 
+    updateReviewComment: publicProcedure
+      .input(z.object({
+        id: z.string().min(1),
+        body: z.string().trim().min(1),
+      }))
+      .mutation(async ({ ctx, input }) => {
+        const repo = requireReviewCommentRepository(ctx);
+        const comment = await repo.update(input.id, input.body);
+        if (!comment) {
+          throw new TRPCError({ code: 'NOT_FOUND', message: `Review comment '${input.id}' not found` });
+        }
+        return comment;
+      }),
+
     resolveReviewComment: publicProcedure
       .input(z.object({ id: z.string().min(1) }))
       .mutation(async ({ ctx, input }) => {