[AlyaGomaa]

Sub-PR of #2141: part 1 of 12. The parent PR stays open and unchanged; this PR carries one feature of it so it can be reviewed on its own.

What this PR adds

• Spawn-safe processes: ModuleProcess and create_process for modules, profiler, evidence handler and input, so Slips starts where fork is not the default (macOS).
• Queue sizes capped to the platform semaphore limit (SEM_VALUE_MAX).
• AID worker opens its own database, stops with its parent (worker_lifecycle.py), and a worker of an older run can no longer write into a newer run's Redis (belongs_to_run checks the main PID).
• Input: stdin flow types with clean shutdown on EOF, nfdump legacy CSV schema, localnet inferred for piped flows.
• Live network state for Linux and macOS (managers/network_state.py): interface addresses, gateway and DNS are refreshed by HostIPManager and stored in Redis (get_network_state, replace_network_state).
• Shared helpers used by later sub-PRs: common/mac.py, common/network_context.py, common/slips_own_traffic.py.
• macOS desktop notifications (mac_notifications.py + Swift helper) and a plain alert text formatter.
• Output.print no longer blocks when another process holds the terminal lock.
• Docs: native macOS install guide, Raspberry Pi memory limits. feel_project pointer moved to the commit that ignores .DS_Store.

Where it sits in the split

• Chain: part 1 of 12. Review and merge in order.
• Base: develop.
• Next: Bound flow storage and keep detection history #2199.
• Size: 95 files, +4085 / -441 lines (tests are +2050 of them).
• Built from parent head 8d6533186.

Notes for review

• Test setup: conftest.py gives each test a fresh ConfigParser; ModuleFactory refuses a Redis that belongs to a running Slips.
• .secrets.baseline is updated here once for the whole split, so it lists files that arrive in later parts.
• develop rewrote tests/unit/slips_files/core/database/test_database.py after the parent branched. The parent's new database tests are appended to develop's version (here and in later parts) and use develop's class-state fixture.
• develop moved the FAQ out of docs/contributing.md; the parent's FAQ edits are applied to docs/FAQ.md.

Tests

• Unit suite on this branch (local, pytest tests/unit -n 3): 3405 passed, 2 skipped, 0 failed. Integration tests were not run locally.