feat: add comprehensive performance benchmark suite

Implement Enhancement #3: Performance benchmarking infrastructure comparing
Ephapax to Rust and AssemblyScript across compilation speed, binary size,
and runtime performance.

Components:
- Criterion benchmarks for compilation time (parse, typecheck, codegen)
- Binary size measurement tool (raw + gzipped WASM)
- Runtime performance benchmarks using wasmtime
- Reference implementations (Fibonacci, Factorial) in all 3 languages
- Comparison scripts (Bash runner + Python report generator)
- GitHub Actions CI integration with weekly runs

Files added (16 total):
- benches/*.rs (3 Criterion benchmarks)
- benches/comparison/* (reference implementations)
- benches/scripts/* (automation)
- .github/workflows/benchmark.yml (CI)
- docs/BENCHMARKS.md (complete guide)

Usage:
  ./benches/scripts/run_all_benchmarks.sh
  cargo bench --bench compile_time
  cargo run --release --bin binary_size

CI Features:
- Runs on push, PR, and weekly schedule
- Generates markdown comparison reports
- Posts results as PR comments
- Archives artifacts for historical tracking

Status: Enhancement #3 complete (100%)
Next: Enhancement #4 (VS Code Extension)

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

Author: Jonathan D.A. Jewell

.github/workflows/benchmark.yml

@@ -0,0 +1,82 @@
+# SPDX-License-Identifier: PMPL-1.0-or-later
+name: Performance Benchmarks
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+    branches: [main]
+  schedule:
+    # Run benchmarks weekly on Monday at 00:00 UTC
+    - cron: '0 0 * * 1'
+
+permissions:
+  contents: write  # For pushing benchmark results
+
+jobs:
+  benchmark:
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@93cb6efe18208431cddfb8368fd83d5badbf9bfd # v5
+
+      - name: Install Rust
+        uses: dtolnay/rust-toolchain@4be9e76fd7c4901c61fb841f559994984270fce7 # stable
+        with:
+          toolchain: stable
+          targets: wasm32-unknown-unknown
+
+      - name: Install Node.js
+        uses: actions/setup-node@v4
+        with:
+          node-version: '20'
+
+      - name: Cache Cargo
+        uses: Swatinem/rust-cache@779680da715d629ac1d338a641029a2f4372abb5 # v2
+
+      - name: Install AssemblyScript dependencies
+        run: |
+          cd benches/comparison/assemblyscript
+          npm install
+
+      - name: Build Ephapax compiler
+        run: cargo build --release
+
+      - name: Run compilation time benchmarks
+        run: cargo bench --bench compile_time -- --output-format bencher | tee compile_output.txt
+
+      - name: Run binary size measurements
+        run: cargo run --release --bin binary_size | tee size_output.txt
+
+      - name: Run runtime performance benchmarks
+        run: cargo bench --bench runtime_perf -- --output-format bencher | tee runtime_output.txt
+
+      - name: Generate comparison report
+        run: |
+          python3 benches/scripts/compare_results.py
+
+      - name: Upload benchmark results
+        uses: actions/upload-artifact@v4
+        with:
+          name: benchmark-results
+          path: |
+            target/criterion/
+            benches/BENCHMARK-RESULTS.md
+            compile_output.txt
+            size_output.txt
+            runtime_output.txt
+
+      - name: Comment PR with results
+        if: github.event_name == 'pull_request'
+        uses: actions/github-script@v7
+        with:
+          script: |
+            const fs = require('fs');
+            const report = fs.readFileSync('benches/BENCHMARK-RESULTS.md', 'utf8');
+
+            github.rest.issues.createComment({
+              issue_number: context.issue.number,
+              owner: context.repo.owner,
+              repo: context.repo.repo,
+              body: `## 📊 Benchmark Results\n\n${report}`
+            });

Cargo.toml

@@ -56,3 +56,28 @@ ariadne = "0.4"
 clap = { version = "4", features = ["derive"] }
 colored = "2"
 rustyline = "14"
+
+# Benchmarking dependencies
+criterion = { version = "0.5", features = ["html_reports"] }
+wasmtime = "27"
+
+# Benchmark binaries
+[[bin]]
+name = "binary_size"
+path = "benches/binary_size.rs"
+required-features = []
+
+[dev-dependencies]
+criterion.workspace = true
+wasmtime.workspace = true
+ephapax-syntax.workspace = true
+ephapax-typing.workspace = true
+ephapax-wasm.workspace = true
+
+[[bench]]
+name = "compile_time"
+harness = false
+
+[[bench]]
+name = "runtime_perf"
+harness = false