docs: Specify internal refactoring to use conn.config

All runtime operations must use self.connection.config instead of
global config:
- table.py: safemode for delete/drop
- schemas.py: safemode, create_tables
- preview.py: display settings
- diagram.py: diagram_direction
- jobs.py: all jobs settings
- autopopulate.py: jobs settings
- declare.py: add_job_metadata
- connection.py: reconnect, query_cache
- hash_registry.py, codecs: stores, download_path

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: dimitri-yatsenko

docs/design/thread-safe-mode.md

@@ -34,7 +34,7 @@ conn = dj.Connection(
 
 # Modify settings per-connection
 conn.config.safemode = False
-conn.config.display_limit = 25
+conn.config.display.limit = 25
 
 schema = dj.Schema("my_schema", connection=conn)
 ```
@@ -71,22 +71,68 @@ conn.config.stores = {...}   # Configure stores for this connection
 
 ## Implementation
 
-1. Add `thread_safe: bool = False` field to `Config` with `DJ_THREAD_SAFE` env alias
-2. Make `thread_safe` always read-only after initialization
-3. When `thread_safe=True`, make `dj.config` writes raise `ThreadSafetyError`
-4. Add guard to `dj.conn()`
-5. Add guard to `Schema.__init__` when `connection=None`
-6. Add `conn.config` to `Connection` that copies from global `dj.config`
-7. Add `ThreadSafetyError` exception
+### 1. Add thread_safe setting
+- Add `thread_safe: bool = False` field to `Config` with `DJ_THREAD_SAFE` env alias
+- Make `thread_safe` always read-only after initialization
+- When `thread_safe=True`, make `dj.config` writes raise `ThreadSafetyError`
 
-## Exceptions
+### 2. Add guards for global state
+- `dj.conn()`: Raise `ThreadSafetyError` when `thread_safe=True`
+- `Schema.__init__`: Raise `ThreadSafetyError` when `connection=None` and `thread_safe=True`
+
+### 3. Add conn.config
+- `Connection.__init__`: Create `self.config` as copy of global `dj.config`
+- `conn.config` is always mutable
+
+### 4. Refactor internal code to use conn.config
+
+All runtime operations must use `self.connection.config` instead of global `config`:
+
+**table.py:**
+- `Table.delete()`: Use `self.connection.config.safemode`
+- `Table.drop()`: Use `self.connection.config.safemode`
+
+**schemas.py:**
+- `Schema.drop()`: Use `self.connection.config.safemode`
+- `Schema.__init__`: Use `self.connection.config.database.create_tables`
+
+**preview.py:**
+- Use `connection.config.display.limit`
+- Use `connection.config.display.width`
+- Use `connection.config.display.show_tuple_count`
+- Note: Preview functions need connection passed in or accessed via table
+
+**diagram.py:**
+- Use `schema.connection.config.display.diagram_direction`
+
+**jobs.py:**
+- Use `self.connection.config.jobs.*` for all jobs settings
+- `version_method`, `default_priority`, `stale_timeout`, `keep_completed`
+
+**autopopulate.py:**
+- Use `self.connection.config.jobs.allow_new_pk_fields_in_computed_tables`
+- Use `self.connection.config.jobs.auto_refresh`
+
+**declare.py:**
+- Use `connection.config.jobs.add_job_metadata`
+
+**connection.py:**
+- Use `self.config.database.reconnect` for reconnect behavior
+- Use `self.config.query_cache` for query caching
+
+**hash_registry.py, staged_insert.py, builtin_codecs/\*:**
+- Use `connection.config.get_store_spec()` for store configuration
+- Use `connection.config.download_path` for downloads
+
+### 5. Add ThreadSafetyError exception
 
 ```python
 class ThreadSafetyError(DataJointError):
     """Raised when modifying global state in thread-safe mode."""
 ```
 
-Error messages:
+## Error Messages
+
 - Config write: `"Global config is read-only in thread-safe mode. Use conn.config for connection-scoped settings."`
 - `dj.conn()`: `"dj.conn() is disabled in thread-safe mode. Use Connection() with explicit parameters."`
 - Schema without connection: `"Schema requires explicit connection in thread-safe mode."`