docs: add dogfooding results and changelog

CHANGELOG.md

@@ -0,0 +1,34 @@
+# Changelog
+
+All notable changes to goperf will be documented in this file.
+
+## [0.1.0] - 2026-01-05
+
+### Added
+- Initial release with 9 rule categories:
+  - **algorithm**: Nested range loops, linear search in loops
+  - **allocation**: Unpreallocated slices, string concatenation, map size hints
+  - **database**: SQL in loops (N+1), unbatched inserts, connection pool issues
+  - **concurrency**: Unbuffered channels, mutex in loops, goroutine leaks
+  - **io**: JSON in loops, HTTP client creation, ReadAll usage, body close
+  - **cache**: Repeated regexp/template compilation
+  - **context**: Background in handlers, missing timeouts, context leaks
+  - **memory**: pprof in hot paths, large struct copies
+  - **benchmark**: Functions needing benchmarks
+
+- Output formats: `console`, `json`, `diff`
+- CI integration with `--fail-on` threshold
+- Auto-fix suggestions with `--fix` and `--dry-run`
+- Ignore comments: `// perf:ignore`, `// perf:ignore-start/end`
+- Smart detection to reduce false positives:
+  - Recognizes prepared statements in database loops
+  - Detects signal channels (`done`, `quit`, `ctx`)
+  - Identifies bounded loops with small iteration counts
+
+### Dogfooding Results
+Ran goperf on itself:
+- **Before**: 147 issues (36 medium, 111 low)
+- **Fixed**: 34 issues (slice preallocation, strings.Builder, map hints)
+- **After**: 113 issues (3 medium, 110 low)
+
+The 3 remaining medium issues are intentional AST traversal patterns, and the 110 low issues are benchmark suggestions.

README.md

@@ -183,6 +183,39 @@ for _, other := range others {
 // perf:ignore-end
 ```
 
+## Dogfooding: goperf on Itself
+
+We run `goperf` on its own codebase. Here's what happened:
+
+```
+$ goperf ./...
+╭───────────────────────────────────────────────────────────────────╮
+│ PERF-AUDIT: 147 issues found (36 medium, 111 low)                 │
+╰───────────────────────────────────────────────────────────────────╯
+```
+
+**We fixed all 34 actionable issues:**
+
+| Issue Type | Count | Fix Applied |
+|------------|-------|-------------|
+| Unpreallocated slices | 31 | `make([]T, 0, N)` with capacity hints |
+| String concat in loops | 2 | `strings.Builder` |
+| Map without size hint | 1 | `make(map[K]V, size)` |
+
+**After fixes:**
+```
+$ goperf ./...
+╭───────────────────────────────────────────────────────────────────╮
+│ PERF-AUDIT: 113 issues found (3 medium, 110 low)                  │
+╰───────────────────────────────────────────────────────────────────╯
+```
+
+The remaining 113 issues are:
+- **3 medium**: Nested loops for AST traversal (intentional, not O(n²) on data)
+- **110 low**: "Consider adding benchmarks" suggestions
+
+This demonstrates that `goperf` finds real issues - including in itself - and that fixing them is straightforward.
+
 ## Contributing
 
 Contributions welcome! Areas we'd love help with: