feat(diagnostics): detect declare(strict_types=1) for stricter type checking

[calebdw]

Reads declare(strict_types=1) from the calling file and tightens call-argument type checking accordingly.

Under strict types, PHP's implicit scalar call-time coercions are now flagged in type_mismatch_argument diagnostics:

• int/float -> string
• numeric-string -> int/float
• numeric-string literals -> integer range parameters when strict types are enabled

The int -> float exception is preserved to match PHP runtime semantics. Concatenation and other non-call contexts are unaffected because this change is scoped to call argument diagnostics only.

The implementation is hardened by preserving literal kinds for int, float, and string values instead of flattening literals to raw strings. That avoids cases like 1.0 being misclassified as an integer and keeps PHP numeric syntaxes such as underscores, scientific notation, and hex/binary/octal integers meaningful during compatibility checks.

Includes focused tests for:

• strict int -> string mismatches
• strict float -> string mismatches
• non-strict numeric coercion baselines
• strict and non-strict numeric-string literal behavior
• integer range checks for decimal and hex integer literals
• rejection of float literals for integer ranges
• preserved int -> float behavior
• concatenation remaining unaffected

Closes #203

[codecov-commenter]

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Codecov Report

❌ Patch coverage is 74.91639% with 75 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
src/php_type.rs	83.75%	32 Missing ⚠️
src/diagnostics/type_errors.rs	66.21%	25 Missing ⚠️
src/completion/types/conditional.rs	30.43%	16 Missing ⚠️
src/completion/variable/forward_walk.rs	33.33%	2 Missing ⚠️

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