Add php-assumptions support for explicit assumption analysis

[coisa]

Problem

php-assumptions introduces explicit runtime/compile-time assumption checks, but dev-tools currently focuses on generic static checks.

Without explicit assumptions, contracts and invariants may be spread implicitly across code without a central quality check.

Proposal

Evaluate adding php-assumptions support in an optional analysis mode.

Plan:

• Add a command extension under an analyse entrypoint (new or existing).
• Ship with safe defaults, allow local config passthrough, and expose list/format controls.
• Keep it non-blocking unless explicitly enabled.

Goals

• Encourage explicit assumption-driven testability and API clarity.
• Keep rule output stable and auditable.
• Keep runtime overhead contained to opted-in pipelines.

Expected Benefits

• Better signal for hidden assumptions and undefined expectations.
• Improved consistency in codebase-wide contract documentation.

Why Not (if skipped)

• Some teams may already use other assumption frameworks.
• Misconfigured assumptions can produce noise in legacy repositories.

Non-goals

• Replacing Rector/PHPStan baseline checks.
• Enforcing assumptions with strict zero-tolerance from day one.

Acceptance Criteria

• A clear decision matrix is recorded (on/off per repo profile).
• Command/docs explain defaults and local override strategy.
• Output is deterministic and does not mutate behavior outside analysis mode.

Architectural / Isolation Criteria

• MUST: Keep assumption checks in a dedicated analysis service, not embedded in command wiring.
• MUST: Respect local configuration precedence over packaged defaults.