docs: update changelog and add CLAUDE.md project guidelines

Add changelog entries for fixes #2, #3, #12, #15, #22.
Add CLAUDE.md with branch workflow and review conventions.

Author: Ignacio Van Droogenbroeck

CHANGELOG.md

@@ -15,6 +15,11 @@
 - **decode:** cap `DecodeMap()` allocation at `maxMapSize` (1M) — same OOM vector for `map[string]interface{}` path
 - **decode:** fix `disableAllocLimitFlag` check in `decodeSliceValue` — `!= 1` was always true because the flag value is `1 << 3 = 8`, so the alloc limit in `growSliceValue()` was never applied
 - **decode:** fix error message in `DecodeFloat64` — said "decoding float32" instead of "decoding float64" ([#13](https://github.com/Basekick-Labs/msgpack/issues/13))
+- **decode:** allow float-encoded values to decode into `int64`/`uint64` with validation — rejects NaN, Inf, fractional, and out-of-range values ([#2](https://github.com/Basekick-Labs/msgpack/issues/2))
+- **decode:** allow `float64`-encoded values to decode into `float32` with overflow check ([#12](https://github.com/Basekick-Labs/msgpack/issues/12))
+- **encode:** handle non-addressable values with pointer receivers — `ensureAddr` creates an addressable copy instead of returning an error ([#3](https://github.com/Basekick-Labs/msgpack/issues/3))
+- **encode:** prevent panic when marshalling `reflect.Value` — unwraps and encodes the underlying value ([#15](https://github.com/Basekick-Labs/msgpack/issues/15))
+- **encode:** preserve custom error types instead of reducing to plain strings via `.Error()` ([#22](https://github.com/Basekick-Labs/msgpack/issues/22))
 
 ### Chores
 

CLAUDE.md

@@ -0,0 +1,37 @@
+# Project Guidelines
+
+## Branch Workflow
+
+- Create a **separate branch** for every fix/feature before making changes.
+- Branch naming: `fix/<short-description>` for bugs, `feat/<short-description>` for features.
+- Base branches off `v6` (the main development branch).
+- Each branch should be committed and a PR created against `v6`.
+
+## Code Review
+
+- After completing each fix, run a review agent to check for:
+  - Redundant or duplicated code
+  - Elegance and idiomatic Go style
+  - Correctness and edge cases
+  - Whether the change would pass review by a senior/staff engineer
+- Do not consider a fix done until it passes review.
+
+## Project Context
+
+- Performance-optimized fork of `vmihailenco/msgpack/v5`, maintained by Basekick Labs.
+- Built for Arc, a high-performance time-series database.
+- Upstream module path (`github.com/vmihailenco/msgpack/v5`) preserved for drop-in compatibility.
+- Go version: 1.26+
+
+## Testing
+
+- Run `go test ./...` to validate changes.
+- Run `go test -race ./...` for race condition checks.
+- Test files use testify/suite pattern (`MsgpackTest` suite).
+- Type tests in `types_test.go` use `typeTest` structs.
+
+## Code Style
+
+- Keep changes minimal and focused.
+- Avoid unnecessary refactoring around the fix.
+- Add test cases for every bug fix.