[launch_manager] Replace floating point seconds with integer milliseconds for timing configuration #345

What

Problem: Timing configuration currently uses floating-point seconds. Floating-point values are prone to computational rounding errors and increase the verification burden for safety-critical code paths.

Proposal: Replace all timing-related configuration values expressed as floating-point seconds with integer milliseconds. Use integers (ms) everywhere in configuration files, parsing, internal representation, and public APIs to remove floating-point arithmetic from timing config.

Benefits:

• Eliminates floating-point rounding issues in configuration values.
• Reduces safety verification scope and simplifies reasoning about timing.
• Provides consistent, unambiguous units across the codebase.

Acceptance Criteria (DoD)

• No floating-point numbers used for timing configuration anywhere in Launch Manager codebase, configs, or public APIs.
• All timing configuration fields documented as integer milliseconds.
• Tests updated and passing.

How

No response