Api construction for authentiations and File Integrity

[AdityaPatadiya]

Added below api endpoints:

Authentication:

POST /auth/register
Purpose: Register a new user.
Auth: Public (no token required).
Request: JSON matching [UserCreate](vscode-file://vscode-app/opt/visual-studio-code/resources/app/out/vs/code/electron-browser/workbench/workbench.html) schema (likely { username, email, password }).
Response: Created user info and access token (uses [register_user](vscode-file://vscode-app/opt/visual-studio-code/resources/app/out/vs/code/electron-browser/workbench/workbench.html) service). Returns token, user object (id, username, email, is_admin) and message. First registered user may be admin depending on service logic.
Notes: Calls [register_user](vscode-file://vscode-app/opt/visual-studio-code/resources/app/out/vs/code/electron-browser/workbench/workbench.html) service which hashes the password, creates the user in DB and issues JWT.

POST /auth/login
Purpose: Authenticate a user and return a token.
Auth: Public.
Request: JSON matching [UserLogin](vscode-file://vscode-app/opt/visual-studio-code/resources/app/out/vs/code/electron-browser/workbench/workbench.html) schema (likely { email, password }).
Response: Access token, token_type "bearer", user object (id, username, email, is_admin), message.
Notes: Uses [login_user](vscode-file://vscode-app/opt/visual-studio-code/resources/app/out/vs/code/electron-browser/workbench/workbench.html) service that verifies password and issues token.

GET /auth/me
Purpose: Return the currently authenticated user's profile.
Auth: Requires valid token (Depends on [verify_token](vscode-file://vscode-app/opt/visual-studio-code/resources/app/out/vs/code/electron-browser/workbench/workbench.html)).
Request: No body; token provided via Authorization header (Bearer).
Response: { id, username, email, is_admin } for the token's subject.
Errors: 404 if user not found.

GET /auth/users
Purpose: Return list of all users.
Auth: Admin-only (enforced by helper [verify_admin_access](vscode-file://vscode-app/opt/visual-studio-code/resources/app/out/vs/code/electron-browser/workbench/workbench.html) which checks token and DB is_admin).
Request: None (token required).
Response: Array of user objects { id, username, email, is_admin }.
Errors: 403 if not admin.

POST /auth/users
Purpose: Create a new user (admin-only).
Auth: Admin-only.
Request: [UserCreate](vscode-file://vscode-app/opt/visual-studio-code/resources/app/out/vs/code/electron-browser/workbench/workbench.html) JSON.
Response: Same as register (calls [register_user](vscode-file://vscode-app/opt/visual-studio-code/resources/app/out/vs/code/electron-browser/workbench/workbench.html)).
Errors: 400 if email already registered.

PUT /auth/users/{user_id}
Purpose: Update an existing user (admin-only).
Auth: Admin-only.
Request: [UserCreate](vscode-file://vscode-app/opt/visual-studio-code/resources/app/out/vs/code/electron-browser/workbench/workbench.html)-like payload (username, email, password).
Response: Updated user object { id, username, email, is_admin }.
Notes: If the password field is present, it's re-hashed. Prevents duplicate email across other users. Commits/refreshes the user after changes.
Errors: 404 if user not found; 400 if new email is already in use.

DELETE /auth/users/{user_id}
Purpose: Delete a user (admin-only).
Auth: Admin-only.
Request: Path param user_id.
Response: { message: "User deleted successfully" }.
Notes: Admin cannot delete their own account (400). Commits deletion.
Errors: 404 if user not found.

PUT /auth/users/{user_id}/admin
Purpose: Toggle admin status for a user (promote/demote).
Auth: Admin-only.
Request: Path param user_id.
Response: Updated user object and message indicating promoted/demoted.
Notes: Admin cannot toggle their own admin status (400). Commits and refreshes user.
Errors: 404 if user not found.

File Integrity:

POST /api/fim/start
Purpose: Start file integrity monitoring for provided directories.
Auth: Admin-only (depends on [verify_admin_access](vscode-file://vscode-app/opt/visual-studio-code/resources/app/out/vs/code/electron-browser/workbench/workbench.html)).
Request: [FIMStartRequest](vscode-file://vscode-app/opt/visual-studio-code/resources/app/out/vs/code/electron-browser/workbench/workbench.html) schema (likely { directories: List[str], excluded_files?: List[str] }).
Response: { message, directories, excluded_files } on success.
Side effects:
Validates directories exist on disk.
Ensures directories are in the FIM DB (creates missing Directory records).
Commits DB changes.
Adds a Background task that runs [fim_monitor.monitor_changes(admin_username, directories, excluded_files)](vscode-file://vscode-app/opt/visual-studio-code/resources/app/out/vs/code/electron-browser/workbench/workbench.html).
Errors: 400 for non-existent directories; 500 for failures. Rolls back FIM DB on exception.

POST /api/fim/stop
Purpose: Stop monitoring.
Auth: Admin-only.
Request: [FIMStopRequest](vscode-file://vscode-app/opt/visual-studio-code/resources/app/out/vs/code/electron-browser/workbench/workbench.html) (likely { directories: List[str] } or maybe empty); body validated by schema.
Response: { message, stopped_directories }.
Side effects: Stops observer thread if alive.
Errors: 500 on failure.

GET /api/fim/status
Purpose: Get monitoring status and watched directories.
Auth: Token required (verify_token) — not strictly admin-only (uses token dependency).
Request: None (token required).
Response: [FIMStatusResponse](vscode-file://vscode-app/opt/visual-studio-code/resources/app/out/vs/code/electron-browser/workbench/workbench.html) model containing:
is_monitoring (bool)
watched_directories (List[str])
total_watched (int)
Notes: Reads [fim_monitor.observer](vscode-file://vscode-app/opt/visual-studio-code/resources/app/out/vs/code/electron-browser/workbench/workbench.html) liveness and Directory table in FIM DB. 500 on errors.

GET /api/fim/changes
Purpose: Fetch detected file changes (added/modified/deleted).
Auth: Token required (verify_token).
Request: Optional query param [directory](vscode-file://vscode-app/opt/visual-studio-code/resources/app/out/vs/code/electron-browser/workbench/workbench.html) to filter changes.
Response: [FIMChangesResponse](vscode-file://vscode-app/opt/visual-studio-code/resources/app/out/vs/code/electron-browser/workbench/workbench.html) model (added, modified, deleted maps and total_changes).
Notes:
Queries [FileMetadata](vscode-file://vscode-app/opt/visual-studio-code/resources/app/out/vs/code/electron-browser/workbench/workbench.html) rows where status != 'current', optionally filtered by directory.
Organizes changes into three dicts keyed by item path; includes hash, last_modified, type, detected_at.
Uses [detected_at](vscode-file://vscode-app/opt/visual-studio-code/resources/app/out/vs/code/electron-browser/workbench/workbench.html) descending.
500 on failure.

GET /api/fim/logs
Purpose: Retrieve FIM log files.
Auth: Token required (verify_token).
Request: Optional query param [directory](vscode-file://vscode-app/opt/visual-studio-code/resources/app/out/vs/code/electron-browser/workbench/workbench.html) to fetch logs only for that directory.
Response: List of [FIMLogsResponse](vscode-file://vscode-app/opt/visual-studio-code/resources/app/out/vs/code/electron-browser/workbench/workbench.html) objects containing { directory, log_file, content }.
Notes:
Reads files under project logs folder named FIM_<dir>.log.
404 if no logs found for requested directory or no logs at all.
Handles IO and returns 500 otherwise.

POST /api/fim/restore
Purpose: Restore files from backup for a given path.
Auth: Admin-only.
Request: [FIMRestoreRequest](vscode-file://vscode-app/opt/visual-studio-code/resources/app/out/vs/code/electron-browser/workbench/workbench.html) (likely { path_to_restore: str }).
Response: { message, restored_path } if successful.
Side effects: Calls [Backup().restore_backup(path, admin_username)](vscode-file://vscode-app/opt/visual-studio-code/resources/app/out/vs/code/electron-browser/workbench/workbench.html).
Errors: 400 if restore returns falsy; 500 on exceptions.

POST /api/fim/add-path
Purpose: Add a new directory to the monitoring list.
Auth: Admin-only.
Request: [FIMAddPathRequest](vscode-file://vscode-app/opt/visual-studio-code/resources/app/out/vs/code/electron-browser/workbench/workbench.html) schema (likely { directory: str }).
Response: { message, directory, total_monitored }.
Side effects:
Validates directory exists on disk.
Inserts new Directory record into FIM DB.
Optionally appends to [fim_monitor.current_directories](vscode-file://vscode-app/opt/visual-studio-code/resources/app/out/vs/code/electron-browser/workbench/workbench.html) if monitoring active.
Errors: 400 if directory doesn't exist or is already monitored, 500 on failure.

POST /api/fim/reset-baseline
Purpose: Reset baseline for specified directories (recalculate baseline).
Auth: Admin-only.
Request: [FIMStartRequest](vscode-file://vscode-app/opt/visual-studio-code/resources/app/out/vs/code/electron-browser/workbench/workbench.html) schema (reused; contains directories list).
Response: { message, directories } on success.
Side effects: Calls [fim_monitor.reset_baseline(admin_username, directories)](vscode-file://vscode-app/opt/visual-studio-code/resources/app/out/vs/code/electron-browser/workbench/workbench.html).
Errors: 500 on failure.

GET /api/fim/baseline
Purpose: Get current baseline entries (status == 'current') for all or a specific directory.
Auth: Token required (verify_token).
Request: Optional query param [directory](vscode-file://vscode-app/opt/visual-studio-code/resources/app/out/vs/code/electron-browser/workbench/workbench.html).
Response: { baseline: { directory_path: { item_path: { type, hash, last_modified } } }, total_items: int }
Notes:
If directory parameter provided and not found, returns 404.
500 on other failures.

• Rest of the apis will be implementated sooner....