Improve config lookup and OpenAI streaming decode

dev-plan.md

@@ -8,7 +8,7 @@
 ## Functional Requirements
 - **Interactive chat loop** Allow continuous message exchange with the AI until the user exits.
 - **Config-driven startup** Parse `config.yaml` for `api.url`, `api.key`, model defaults, and future options (e.g., system prompts, temperature, streaming flag).
-- **Persistent history** Store chats in a SQLite database located at `/var/log/goaichat/<username>/goaichat.db`, capturing session metadata and full message transcripts.
+- **Persistent history** Store chats in a SQLite database located at `$HOME/.local/share/goaichat/goaichat.db` (configurable), capturing session metadata and full message transcripts.
 - **History commands** Provide `/list` to enumerate saved chats and allow selecting or reopening them within the session.
 - **Model management** Support `/models` command to display configured/available models, persist the user’s choice, and use it for subsequent requests.
 - **Graceful exit controls** Support commands like `/exit`, `/reset`, `/help`.
@@ -44,20 +44,17 @@ dflow LR
     ChatCore --> UI
     Config[(config.yaml + env)] --> ConfigPkg[Configuration]
     ConfigPkg --> AppCore[Application core]
-    AppCore --> UI
     AppCore --> ChatCore
     AppCore --> OpenAIClient
     AppCore --> Storage
-```
-
-## Persistence & Data Storage (`internal/storage`)
-- **Data directory** Resolve user-specific path `/var/log/goaichat/<username>/` (configurable override) and ensure directories exist with secure permissions.
-- **Database** SQLite file `goaichat.db` managed via `modernc.org/sqlite` (pure Go) for portability; allow build tag to switch to `mattn/go-sqlite3` if desired.
-- **Schema**
-  - **`sessions`** (`id`, `name`, `created_at`, `updated_at`, `model_name`, `summary`).
-  - **`messages`** (`id`, `session_id`, `role`, `content`, `token_count`, `created_at`).
-  - **`models`** (`id`, `name`, `display_name`, `provider`, `is_default`, `last_used_at`).
-- **Migrations** Ship SQL migration files applied on startup; version using goose/atlas or simple in-app migration runner.
+##- **Persistence & Data Storage (`internal/storage`)
+  - **Data directory** Resolve user-specific path `$HOME/.local/share/goaichat/` (configurable override) and ensure directories exist with secure permissions.
+  - **Database** SQLite file `goaichat.db` managed via `modernc.org/sqlite` (pure Go) for portability; allow build tag to switch to `mattn/go-sqlite3` if desired.
+  - **Schema**
+    - **`sessions`** (`id`, `name`, `created_at`, `updated_at`, `model_name`, `summary`).
+    - **`messages`** (`id`, `session_id`, `role`, `content`, `token_count`, `created_at`).
+    - **`models`** (`id`, `name`, `display_name`, `provider`, `is_default`, `last_used_at`).
+{{ ... }}
 - **Data access** Provide repository interfaces for chat service to create sessions, append messages, list chats, update selected model, and fetch transcripts.
 - **Performance** Enable write-ahead logging, tune connection settings, and guard concurrent access with a request queue or mutex.
 
@@ -127,7 +124,7 @@ logging:
 - **Milestone 4: Persistence foundation**
   - **Design** SQLite schema and migrations within `internal/storage`.
   - **Implement** repositories for sessions, messages, and models.
-  - **Ensure** path resolution to `/var/log/goaichat/<username>/` with permission checks and tests.
+  - **Ensure** path resolution to `$HOME/.local/share/goaichat/` with permission checks and tests.
 
 - **Milestone 5: Chat loop MVP**
   - **Implement** CLI loop that reads user input, calls chat client, prints responses.