[INJECT-09] Add fuzzing and hostile-input resource limits

[chrisbbreuer]

Objective

Fuzz SQL, HTML5, XSS, callback, embedded-NUL, malformed UTF-8, and oversized inputs; enforce bounded work and prove no panics, leaks, or out-of-bounds access.

Deliverables

• Implement the complete scoped behavior without Git submodules.
• Keep public APIs explicit about ownership, resource limits, and errors.
• Add focused unit, integration, compatibility, fuzz, and benchmark coverage as applicable.
• Update documentation and machine-readable compatibility status.

Acceptance criteria

• The scoped implementation and tests are merged on main.
• Zig formatting, focused tests, and the repository CI suite pass.
• No unexplained compatibility skips, silent fallbacks, leaks, or unbounded hostile-input paths remain.
• Benchmarks or security evidence is attached when this affects a hot or untrusted path.

Relationships

• Parent: INJECT-00

Blocked by

• INJECT-05
• INJECT-07

Blocks

• INJECT-10
• INJECT-11

Baselines

• Zig 0.17-dev resolved and locked through Pantry.
• ModSecurity 3.0.16, Coraza 3.7.0, CRS 4.28.0, and libinjection 4.0.0 where applicable.