refactor(projects/sidebar): remove temp snapshot side-effects and simplify session metadata UX

Why this change was needed:
- Project listing had an implicit side effect: every fetch wrote a debug snapshot under `.tmp/project-dumps`.
  That added unnecessary disk I/O to a hot path, introduced hidden runtime behavior, and created maintenance
  overhead for code that was not part of product functionality.
- Keeping snapshot-specific exports/tests around made the projects module API broader than needed and coupled
  tests to temporary/debug behavior instead of user-visible behavior.
- Codex sessions could remain stuck with a placeholder name (`Untitled Codex Session`) even after a real title
  became available from newer sync data, which degraded session discoverability in the UI.
- Sidebar session rows showed duplicated provider branding and long-form relative times, which added visual noise
  and reduced scan speed when many sessions are listed.

What changed:
- Removed temporary projects snapshot dumping from `projects-with-sessions-fetch.service.ts`:
  - deleted snapshot types/helpers and file-write flow
  - removed the write call from `getProjectsWithSessions`
- Removed snapshot-related surface area from `projects/index.ts`.
- Removed the snapshot-focused test `projects.service.test.ts` that only validated removed debug behavior.
- Updated `codex-session-synchronizer.provider.ts` to upgrade session names when an existing session still has
  the placeholder title but a real parsed name is now available.
- Updated `SidebarSessionItem.tsx`:
  - removed duplicate provider logo rendering in each session row
  - moved age indicator to the right side
  - made age indicator fade on hover to prioritize action controls
  - switched to compact relative time format (`<1m`, `Xm`, `Xhr`, `Xd`) for faster list scanning

Outcome:
- Lower overhead and fewer hidden side effects in project fetches.
- Cleaner module boundaries in projects.
- Better Codex session naming consistency after sync.
- Cleaner sidebar density and clearer hover/action behavior.

src/components/sidebar/view/subcomponents/SidebarSessionItem.tsx

@@ -1,8 +1,8 @@
-import { Check, Clock, Edit2, Trash2, X } from 'lucide-react';
+import { Check, Edit2, Trash2, X } from 'lucide-react';
 import type { TFunction } from 'i18next';
+
 import { Badge, Button } from '../../../../shared/view/ui';
 import { cn } from '../../../../lib/utils';
-import { formatTimeAgo } from '../../../../utils/dateUtils';
 import type { Project, ProjectSession, LLMProvider } from '../../../../types/app';
 import type { SessionWithProvider } from '../../types/types';
 import { createSessionViewModel } from '../../utils/utils';
@@ -30,6 +30,34 @@ type SidebarSessionItemProps = {
   t: TFunction;
 };
 
+/**
+ * Compact relative time for sidebar rows:
+ * <1m, Xm, Xhr, Xd.
+ */
+const formatCompactSessionAge = (dateString: string, currentTime: Date): string => {
+  const date = new Date(dateString);
+  if (Number.isNaN(date.getTime())) {
+    return '';
+  }
+
+  const diffInMinutes = Math.floor(Math.max(0, currentTime.getTime() - date.getTime()) / (1000 * 60));
+  if (diffInMinutes < 1) {
+    return '<1m';
+  }
+
+  if (diffInMinutes < 60) {
+    return `${diffInMinutes}m`;
+  }
+
+  const diffInHours = Math.floor(diffInMinutes / 60);
+  if (diffInHours < 24) {
+    return `${diffInHours}hr`;
+  }
+
+  const diffInDays = Math.floor(diffInHours / 24);
+  return `${diffInDays}d`;
+};
+
 export default function SidebarSessionItem({
   project,
   session,
@@ -48,6 +76,7 @@ export default function SidebarSessionItem({
 }: SidebarSessionItemProps) {
   const sessionView = createSessionViewModel(session, currentTime, t);
   const isSelected = selectedSession?.id === session.id;
+  const compactSessionAge = formatCompactSessionAge(sessionView.sessionTime, currentTime);
 
   // Sessions are owned by a project identified by `projectId` (DB primary key)
   // after the projectName → projectId migration.
@@ -94,20 +123,18 @@ export default function SidebarSessionItem({
             </div>
 
             <div className="min-w-0 flex-1">
-              <div className="truncate text-xs font-medium text-foreground">{sessionView.sessionName}</div>
-              <div className="mt-0.5 flex items-center gap-1">
-                <Clock className="h-2.5 w-2.5 text-muted-foreground" />
-                <span className="text-xs text-muted-foreground">
-                  {formatTimeAgo(sessionView.sessionTime, currentTime, t)}
-                </span>
+              <div className="flex items-center gap-2">
+                <div className="truncate text-xs font-medium text-foreground">{sessionView.sessionName}</div>
+                {compactSessionAge && (
+                  <span className="ml-auto flex-shrink-0 text-[11px] text-muted-foreground">{compactSessionAge}</span>
+                )}
+              </div>
+              <div className="mt-0.5 flex items-center">
                 {sessionView.messageCount > 0 && (
-                  <Badge variant="secondary" className="ml-auto px-1 py-0 text-xs">
+                  <Badge variant="secondary" className="px-1 py-0 text-xs">
                     {sessionView.messageCount}
                   </Badge>
                 )}
-                <span className="ml-1 opacity-70">
-                  <SessionProviderLogo provider={session.__provider} className="h-3 w-3" />
-                </span>
               </div>
             </div>
 
@@ -138,23 +165,16 @@ export default function SidebarSessionItem({
           <div className="flex w-full min-w-0 items-start gap-2">
             <SessionProviderLogo provider={session.__provider} className="mt-0.5 h-3 w-3 flex-shrink-0" />
             <div className="min-w-0 flex-1">
-              <div className="truncate text-xs font-medium text-foreground">{sessionView.sessionName}</div>
-              <div className="mt-0.5 flex items-center gap-1">
-                <Clock className="h-2.5 w-2.5 text-muted-foreground" />
-                <span className="text-xs text-muted-foreground">
-                  {formatTimeAgo(sessionView.sessionTime, currentTime, t)}
-                </span>
-                {sessionView.messageCount > 0 && (
-                  <Badge
-                    variant="secondary"
-                    className="ml-auto px-1 py-0 text-xs transition-opacity group-hover:opacity-0"
-                  >
-                    {sessionView.messageCount}
-                  </Badge>
+              <div className="flex items-center gap-2">
+                <div className="truncate text-xs font-medium text-foreground">{sessionView.sessionName}</div>
+                {compactSessionAge && (
+                  <span className="ml-auto flex-shrink-0 text-[11px] text-muted-foreground transition-opacity duration-200 group-hover:opacity-0">
+                    {compactSessionAge}
+                  </span>
                 )}
-                <span className="ml-1 opacity-70 transition-opacity group-hover:opacity-0">
-                  <SessionProviderLogo provider={session.__provider} className="h-3 w-3" />
-                </span>
+              </div>
+              <div className="mt-0.5 flex items-center">
+                {sessionView.messageCount > 0 && <Badge variant="secondary" className="px-1 py-0 text-xs">{sessionView.messageCount}</Badge>}
               </div>
             </div>
           </div>