feat: add HTTP Server benchmark

[algebraic-dev]

This PR adds a HTTP Server benchmark

[mathlib-lean-pr-testing]

Mathlib CI status (docs):

• ❗ Batteries/Mathlib CI will not be attempted unless your PR branches off the nightly-with-mathlib branch. Try git rebase 086e7a357607b2bba9ecf03962b8f0ba90675906 --onto e281ba87c2c967b1662ee28bd201046956d0494a. You can force Mathlib CI using the force-mathlib-ci label. (2026-07-04 02:52:12)
• ❗ Batteries/Mathlib CI will not be attempted unless your PR branches off the nightly-with-mathlib branch. Try git rebase e51752cf2f9a8b305e67ea90c5aa631b210056ce --onto 3259610687883ec1ea48c481aba2469f2f83facf. You can force Mathlib CI using the force-mathlib-ci label. (2026-07-22 15:56:58)

[leanprover-bot]

Reference manual CI status:

• ❗ Reference manual CI will not be attempted unless your PR branches off the nightly-with-manual branch. Try git rebase 086e7a357607b2bba9ecf03962b8f0ba90675906 --onto e281ba87c2c967b1662ee28bd201046956d0494a. You can force reference manual CI using the force-manual-ci label. (2026-07-04 02:52:13)
• ❗ Reference manual CI will not be attempted unless your PR branches off the nightly-with-manual branch. Try git rebase e51752cf2f9a8b305e67ea90c5aa631b210056ce --onto 49ff95727f98d43984726b26742d17a1ceea9dd5. You can force reference manual CI using the force-manual-ci label. (2026-07-22 15:56:59)