feat: resolve dynamic token limits from LiteLLM; unify context usage UI

feat: track STT/TTS models in session; fix audio progress bar; add token usage bar

fix: implement global settings fallback for LLM provider in RAG chat; allow fuzzy model name matching

fix: implement system-settings fallback in STT/TTS routes and resolve missing key 500 error

fix: relax provider health checks and allow non-admin verification for self-provided keys

fix: resolve STT/TTS provider resolution for anonymous/unauthenticated sessions

fix: resolve 'no active stt provider' by ensuring global settings fallback even without user preferences

debug: add verbose TTS logging and strict concurrency of 1 to isolate Google 500 errors

feat: adaptive TTS chunking for lower latency and better stream stability

feat: implement intelligent multi-sentence splitting to eliminate TTS streaming gaps

fix: resolve NameError for logger in TTS route

fix: resolve TTS streaming interruptions via atomic state management and Proxy timeout disabling

fix: resolve 422 validation errors for custom provider names and upgrade error reporting

chore: cleanup test scripts, secure deployment script, and implement Voice/TTS frontend refinements ...

- Removed all temporary root Python test scripts
- Secured remote_deploy.sh credentials using environment variables
- Added data/audio payloads directory to .gitignore
- Added automatic DB migration script (migrate.py) via uvicorn lifespan
- Applied major refactors to UI Voice Chat, Session handling, and unified React API configs
- Updated models and dependencies natively syncing with Nginx proxy features

feat: expose model info to users, multi-model provider cloning, cleaner profile UI ...

- Show model name under each provider button for all users (ProfilePage)
- Admin Settings: upgraded 'Register New Instance' panel with 4 fields:
  provider type, label suffix (with model-name hint), pre-set model
  dropdown, and 'Inherit API Key From' for same-type instance cloning
- Fix API key inheritance: use _clone_from marker instead of copying
  masked key; backend resolves real key from DB before saving
- Lock cloned-key instances: API key field is greyed out with lock icon
  and 'Inherited from <source>' display; Unlink button breaks the link
- Provider card header: show configured model name instead of
  'User Override / System Provided' labels
- ProfilePage: remove confusing 'Do Extra Work' override panel entirely;
  ServiceSelect is now a clean provider selector with no hidden admin UI
- SettingsPage: remove 'User Override' / 'System Provided' badge

Refactor STT model selection to dropdown, add YAML config import/export, and refine Voice/Coding Assistant UI

feat: session history sidebar with feature isolation and auto-titling ...

Backend changes:
- db/models.py: add feature_name column to Session model
- db/models.py: confirmed is_archived col for soft-delete support
- api/schemas.py: expose feature_name on SessionCreate and Session schemas
- core/services/session.py: accept feature_name in create_session()
- api/routes/sessions.py: pass feature_name on creation; add GET /sessions/
  (filtered by user + feature), DELETE /sessions/{id}, DELETE /sessions/
- core/services/rag.py: auto-title session from first user message;
  keep session.provider_name in sync with the model actually used
- core/services/workspace.py: same auto-title + provider_name sync
  on the WebSocket chat path

Frontend changes:
- services/apiService.js: createSession() now sends feature_name and
  provider_name; add getUserSessions(), deleteSession(), deleteAllSessions()
- services/websocket.js: getSessionId() accepts providerName and forwards
  it to createSession so the DB record reflects the real model
- hooks/useCodeAssistant.js: pass 'coding_assistant' namespace + 'deepseek'
  provider; expose handleSwitchSession + sessionId to page
- hooks/useVoiceChat.js: pass 'voice_chat' namespace + 'gemini' provider;
  expose handleSwitchSession + sessionId to page
- components/SessionSidebar.js: new collapsible sidebar (collapsed by default)
  showing history sessions per feature; click to switch, hover to see token
  usage tooltip, per-card delete and bulk 'Clear All'; shows smart relative
  date and provider badge per session
- components/SessionSidebar.css: theme-aware CSS (inherits Tailwind
  light/dark palette; no forced dark mode)
- pages/CodingAssistantPage.js: mount SessionSidebar with coding_assistant
- pages/VoiceChatPage.js: mount SessionSidebar with voice_chat

Tests:
- tests/core/services/test_session_service.py: new unit tests for
  SessionService covering feature_name namespace variants and DB rollback
- tests/api/routes/test_sessions.py: unit tests for new session mgmt routes
  (list by feature, single delete, bulk delete, token usage)
- integration_tests/test_sessions_api.py: end-to-end tests for feature
  isolation, single delete, 404 on missing session, and bulk delete
  confirming cross-feature sessions are unaffected

feat: Add new session UI, token counter, load history, and session isolation

add go-to-production code

enable OIDC

refactor general router

refactor the service container

use litellm underlying

add some logic in workspace

reactor ui project

introduce gcloud tts

add demo code & cors enabled & document the apis

introduce stt endpoint

refactor the routes api to be more modularized

add support of streaming TTS

add tts support from user end

refactor the integration test but tts is broken

refactor retriever

refactor the services to be plugable

add toggle on client side to enable or disable faiss db retriever

support switch model in between

support chat history

introduce the session into the frontend api

introduce the delete document funcs

further refactor

refactor db creation & centralize the config.py

refactor