Add REQUEST_TIME and REQUEST_TIME_FLOAT to server bag

[s2x]

Summary

• Adds REQUEST_TIME (unix timestamp) and REQUEST_TIME_FLOAT (unix timestamp with microseconds) to the server bag in RequestConverter
• Enables Symfony profiler and debug toolbar to show request duration
• Values are set using time() and microtime(true) at request conversion time

Changes

• src/DTO/RequestConverter.php: Added REQUEST_TIME and REQUEST_TIME_FLOAT to the server array
• tests/RequestConverterTest.php: Added unit test testRequestTimeAndRequestTimeFloatAreSet to verify the values are correctly set
• CHANGELOG.md: Added entry under [Unreleased] section

Closes #67

[s2x]

Code Review

Strengths

• Clean, minimal implementation matching the issue spec exactly
• Test covers type assertions and temporal proximity as required
• CHANGELOG entry is clear and links to the issue
• Placement in the server array is logical

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Issues (all must be addressed before merge)

Important

1. tests/RequestConverterTest.php:353 — The assertEqualsWithDelta assertion compares microtime(true) at assertion time against the value captured at conversion time. The 1.0 second delta is generous enough to pass, but it does not verify that REQUEST_TIME and REQUEST_TIME_FLOAT are consistent with each other (i.e., that they represent the same moment). A tighter assertion or capturing microtime(true) before the call would be more rigorous.
   • Why it matters: If someone later changes the order of time() and microtime(true) calls or inserts logic between them, the test would not catch a meaningful drift.
   • How to fix: Capture $before = microtime(true) before the call and assert $symfonyRequest->server->get('REQUEST_TIME_FLOAT') is within a small delta (e.g., 0.1s) of $before.

Minor

2. src/DTO/RequestConverter.php:46-47 — time() and microtime(true) are called separately, which means they could theoretically span a second boundary (e.g., REQUEST_TIME = 1000, REQUEST_TIME_FLOAT = 1001.0001). In practice this is extremely unlikely, but for correctness you could derive REQUEST_TIME from (int) $requestTimeFloat.
   • Why it matters: Edge case correctness; Symfony itself derives REQUEST_TIME from casting REQUEST_TIME_FLOAT.
   • How to fix:

     $requestTimeFloat = microtime(true);
     // ...
     'REQUEST_TIME' => (int) $requestTimeFloat,
     'REQUEST_TIME_FLOAT' => $requestTimeFloat,

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All issues above must be addressed before this PR can be merged.