fix: run tool terminal sessions as container user instead of root

- Remove compose-level user: 0:0 override from manifest_compiler.py so the
  entrypoint can start as root, fix mount ownership, and drop privileges to
  the container user internally.
- Add get_manifest_container_user() helper to resolve the manifest-declared
  container user (with uid:gid fallback).
- Pass container user through TerminalSession, TerminalManager, and the
  terminal WebSocket handler so docker exec is invoked with --user <user>.
- Update and add unit tests for the manifest compiler and terminal session.
- Record the additional root-user fix in the fix-pi-container-mount-permissions
  OpenSpec change/tasks.

Quality gates: pytest tests/unit/ (226 passed), pytest tests/services/test_terminal_manager_multi.py (7 passed), ruff check on changed files (clean), mypy on changed files (clean)

apps/api/src/.pi-map.md

@@ -4,17 +4,17 @@ dir: apps/api/src
 index: apps/api/src/.pi-map.index.md
 
 ## role
-Core backend API package for the "Headquarter API" FastAPI application, handling configuration, database setup, logging, and application bootstrap.
+Core bootstrap and infrastructure package for the Headquarter API FastAPI application, handling configuration, database connectivity, logging, and application startup.
 ## files
 - __init__.py | Marks the directory as a Python package for the Headquarter API.
-- config.py | Defines application configuration settings with environment variable loading, database URL construction, and computed properties for service URLs and security settings. | exp: class:Settings, func:build_database_url(user: str, password: str, host: str, port: int, database: str) → str | dep: pydantic, pydantic_settings
-- database.py | Sets up an async SQLAlchemy database engine with retry logic and runs Alembic migrations via subprocess to initialize the database. | exp: func:init_database(max_retries, retry_delay) → bool, call:range, call:engine.connect, call:test_conn.execute, call:text, call:test_conn.close, call:logger.info, call:asyncio.get_event_loop().run_in_executor, call:subprocess.run, call:os.path.dirname, call:os.path.abspath, call:logger.debug, call:logger.error, call:asyncio.sleep, call:str(exc).lower, call:logger.warning | dep: asyncio, logging, os, subprocess, sqlalchemy.ext.asyncio, sqlalchemy.pool, src.config, sqlalchemy
-- logging_config.py | Configures structured JSON logging with correlation ID injection, request/response logging middleware, and exception handling for a FastAPI application. | exp: class:CorrelationIdFilter, method:filter(self, record: logging.LogRecord) → bool, call:get_correlation_id, class:JSONFormatter, method:format(self, record: logging.LogRecord) → str, call:self.formatTime, call:record.getMessage, call:getattr, call:self.formatException, call:json.dumps, method:formatTime(self, record: logging.LogRecord, datefmt) → str, call:time.strftime, call:time.gmtime, class:RequestLoggingMiddleware, method:dispatch(self, request: Request, call_next: Callable) → Response, call:time.time, call:logger.info, call:call_next, call:int, call:logger.error, call:type, call:traceback.format_exc, class:ExceptionLoggingMiddleware, method:dispatch(self, request: Request, call_next: Callable) → Response, call:call_next, call:logger.critical, call:traceback.format_exc, func:configure_logging(level) → None, call:JSONFormatter, call:logging.StreamHandler, call:console_handler.setFormatter, call:console_handler.addFilter, call:CorrelationIdFilter, call:root_logger.setLevel, call:logging.getLogger("uvicorn").setLevel, call:logging.getLogger("uvicorn.access").setLevel, call:logging.getLogger("sqlalchemy.engine").setLevel, call:logger.info, call:logging.getLevelName | dep: json, logging, sys, time, traceback, collections.abc, fastapi, starlette.middleware.base, src.services.shared.correlation, starlette
-- main.py | Bootstraps a FastAPI application called "Headquarter API" with database initialization, health monitoring, CORS, logging middleware, and modular API routers. | exp: func:_sanitize_validation_errors(errors), call:error.get, call:str, call:ctx.items, call:isinstance, call:type, call:sanitized.append, func:validation_exception_handler(request: Request, exc: RequestValidationError), call:exc.errors, call:logger.warning, call:_sanitize_validation_errors, call:JSONResponse, func:on_startup(), call:logger.info, call:init_database, call:logger.error, call:sys.exit, call:_health_monitor.start, call:seed_builtin_tool_types, func:on_shutdown(), call:logger.info, call:_health_monitor.stop | dep: logging, os, fastapi, fastapi.exceptions, fastapi.middleware.cors, fastapi.responses, fastapi.staticfiles, src.api.config, src.api.project, src.api.system, src.api.tool, src.api.user, src.api.workspace, src.config, src.models, src.database, src.logging_config, src.seeds.builtin_tool_types, src.services.instance, src.services.shared, sys, src.api
+- config.py | Defines application configuration settings with environment-based overrides using Pydantic, including database URLs, domain/public URL resolution, Authentik OAuth integration, session/JWT settings, and cookie security policies. | exp: class:Settings, func:build_database_url(user: str, password: str, host: str, port: int, database: str) → str | dep: pydantic, pydantic_settings
+- database.py | Configures an async SQLAlchemy database engine with session management and provides retry logic for database initialization via Alembic migrations. | exp: func:init_database(max_retries, retry_delay) → bool, call:range, call:engine.connect, call:test_conn.execute, call:text, call:test_conn.close, call:logger.info, call:asyncio.get_event_loop().run_in_executor, call:subprocess.run, call:os.path.dirname, call:os.path.abspath, call:logger.debug, call:logger.error, call:asyncio.sleep, call:str(exc).lower, call:logger.warning | dep: asyncio, logging, os, subprocess, sqlalchemy.ext.asyncio, sqlalchemy.pool, src.config, sqlalchemy
+- logging_config.py | Configures structured JSON logging with correlation IDs and HTTP request/exception middleware for a FastAPI application. | exp: class:CorrelationIdFilter, method:filter(self, record: logging.LogRecord) → bool, call:get_correlation_id, class:JSONFormatter, method:format(self, record: logging.LogRecord) → str, call:self.formatTime, call:record.getMessage, call:getattr, call:self.formatException, call:json.dumps, method:formatTime(self, record: logging.LogRecord, datefmt) → str, call:time.strftime, call:time.gmtime, class:RequestLoggingMiddleware, method:dispatch(self, request: Request, call_next: Callable) → Response, call:time.time, call:logger.info, call:call_next, call:int, call:logger.error, call:type, call:traceback.format_exc, class:ExceptionLoggingMiddleware, method:dispatch(self, request: Request, call_next: Callable) → Response, call:call_next, call:logger.critical, call:traceback.format_exc, func:configure_logging(level) → None, call:JSONFormatter, call:logging.StreamHandler, call:console_handler.setFormatter, call:console_handler.addFilter, call:CorrelationIdFilter, call:root_logger.setLevel, call:logging.getLogger("uvicorn").setLevel, call:logging.getLogger("uvicorn.access").setLevel, call:logging.getLogger("sqlalchemy.engine").setLevel, call:logger.info, call:logging.getLevelName | dep: json, logging, sys, time, traceback, collections.abc, fastapi, starlette.middleware.base, src.services.shared.correlation, starlette
+- main.py | Bootstraps a FastAPI application for "Headquarter API" with CORS, logging, validation error handling, database initialization, health monitoring, and registration of modular API routers. | exp: func:_sanitize_validation_errors(errors), call:error.get, call:str, call:ctx.items, call:isinstance, call:type, call:sanitized.append, func:validation_exception_handler(request: Request, exc: RequestValidationError), call:exc.errors, call:logger.warning, call:_sanitize_validation_errors, call:JSONResponse, func:on_startup(), call:logger.info, call:init_database, call:logger.error, call:sys.exit, call:_health_monitor.start, call:seed_builtin_tool_types, func:on_shutdown(), call:logger.info, call:_health_monitor.stop | dep: logging, os, fastapi, fastapi.exceptions, fastapi.middleware.cors, fastapi.responses, fastapi.staticfiles, src.api.config, src.api.project, src.api.system, src.api.tool, src.api.user, src.api.workspace, src.config, src.models, src.database, src.logging_config, src.seeds.builtin_tool_types, src.services.instance, src.services.shared, sys, src.api.*
 ## arch
-Layered architecture with separation of concerns across config (settings/env), database (async SQLAlchemy with Alembic migrations), logging (structured JSON with middleware), and main (app composition with modular routers and health monitoring).
+Layered infrastructure pattern with Pydantic-based settings management, async SQLAlchemy with Alembic migrations, structured JSON logging with correlation ID tracking, and modular FastAPI router registration with middleware composition.
 ## tags
-src, logging, database, api, call:logger.info, middleware, fastapi, filter
+src, database, logging, api, call:logger.info, fastapi, filter, call:logging.get
 ## symbols
 - Settings
 - CorrelationIdFilter