feat: implement session rename with SQLite storage (#413)

* feat: implement session rename with SQLite storage (closes #72, fixes #358)

- Add session_names table to store custom display names per provider
- Add PUT /api/sessions/:sessionId/rename endpoint
- Replace stub updateSessionSummary with real API call
- Apply custom names across all providers (Claude, Codex, Cursor)
- Fix project rename destroying config (spread merge instead of overwrite)
- Thread provider parameter through sidebar component chain
- Add i18n error messages for rename failures (en, ja, ko, zh-CN)

* fix: address CodeRabbit review feedback for session rename

- Log migration errors instead of swallowing them silently (db.js)
- Add try/catch to applyCustomSessionNames to prevent getProjects abort
- Move applyCustomSessionNames to db.js as shared helper (DRY)
- Fix Cursor getSessionName to check session.summary for custom names
- Move edit state clearing to finally block in updateSessionSummary
- Sanitize sessionId, add 500-char summary limit, validate provider whitelist
- Remove dead applyCustomSessionNames call on empty manual project sessions

* fix: reject sessionId on mismatch instead of silent normalization

Co-authored-by: coderabbitai[bot] <136622811+coderabbitai[bot]@users.noreply.github.com>

* fix: enable rename for all providers, add Gemini support, clean up orphans

- Enable rename UI (pencil icon) for Codex, Cursor, and Gemini sessions
- Keep delete button hidden for Cursor (no backend delete endpoint)
- Add 'gemini' to VALID_PROVIDERS and hoist to module scope
- Add sessionNamesDb.deleteName on session delete (claude, codex, gemini)
- Fix token-usage endpoint sessionId mismatch validation
- Remove redundant try/catch in sessionNamesDb methods
- Let session_names migration errors propagate to outer handler

---------

Co-authored-by: coderabbitai[bot] <136622811+coderabbitai[bot]@users.noreply.github.com>
Co-authored-by: Haileyesus <118998054+blackmammoth@users.noreply.github.com>

src/i18n/locales/en/sidebar.json

@@ -93,6 +93,8 @@
     "enterProjectPath": "Please enter a project path",
     "deleteSessionFailed": "Failed to delete session. Please try again.",
     "deleteSessionError": "Error deleting session. Please try again.",
+    "renameSessionFailed": "Failed to rename session. Please try again.",
+    "renameSessionError": "Error renaming session. Please try again.",
     "deleteProjectFailed": "Failed to delete project. Please try again.",
     "deleteProjectError": "Error deleting project. Please try again.",
     "createProjectFailed": "Failed to create project. Please try again.",

src/i18n/locales/ja/sidebar.json

@@ -93,6 +93,8 @@
     "enterProjectPath": "プロジェクトのパスを入力してください",
     "deleteSessionFailed": "セッションの削除に失敗しました。もう一度お試しください。",
     "deleteSessionError": "セッションの削除でエラーが発生しました。もう一度お試しください。",
+    "renameSessionFailed": "セッション名の変更に失敗しました。もう一度お試しください。",
+    "renameSessionError": "セッション名の変更でエラーが発生しました。もう一度お試しください。",
     "deleteProjectFailed": "プロジェクトの削除に失敗しました。もう一度お試しください。",
     "deleteProjectError": "プロジェクトの削除でエラーが発生しました。もう一度お試しください。",
     "createProjectFailed": "プロジェクトの作成に失敗しました。もう一度お試しください。",

src/i18n/locales/ko/sidebar.json

@@ -93,6 +93,8 @@
     "enterProjectPath": "프로젝트 경로를 입력해주세요",
     "deleteSessionFailed": "세션 삭제 실패. 다시 시도해주세요.",
     "deleteSessionError": "세션 삭제 오류. 다시 시도해주세요.",
+    "renameSessionFailed": "세션 이름 변경 실패. 다시 시도해주세요.",
+    "renameSessionError": "세션 이름 변경 오류. 다시 시도해주세요.",
     "deleteProjectFailed": "프로젝트 삭제 실패. 다시 시도해주세요.",
     "deleteProjectError": "프로젝트 삭제 오류. 다시 시도해주세요.",
     "createProjectFailed": "프로젝트 생성 실패. 다시 시도해주세요.",

src/i18n/locales/zh-CN/sidebar.json

@@ -93,6 +93,8 @@
     "enterProjectPath": "请输入项目路径",
     "deleteSessionFailed": "删除会话失败，请重试。",
     "deleteSessionError": "删除会话时出错，请重试。",
+    "renameSessionFailed": "重命名会话失败，请重试。",
+    "renameSessionError": "重命名会话时出错，请重试。",
     "deleteProjectFailed": "删除项目失败，请重试。",
     "deleteProjectError": "删除项目时出错，请重试。",
     "createProjectFailed": "创建项目失败，请重试。",