build: rename output directory from build/ to bin/

Consolidates build artifact output to bin/ for consistency with
Go project conventions. Updates Makefile BUILD_DIR, Dockerfile
COPY path, README onboard instructions, and gitignore entries.

.gitignore

@@ -1,7 +1,6 @@
 # Binaries
 # Go build artifacts
 bin/
-build/
 *.exe
 *.dll
 *.so
@@ -18,7 +17,6 @@ cmd/picoclaw/workspace
 .picoclaw/
 config.json
 sessions/
-build/
 
 # Coverage
 

Dockerfile

@@ -27,7 +27,7 @@ HEALTHCHECK --interval=30s --timeout=3s --start-period=5s --retries=3 \
   CMD wget -q --spider http://localhost:18790/health || exit 1
 
 # Copy binary
-COPY --from=builder /src/build/picoclaw /usr/local/bin/picoclaw
+COPY --from=builder /src/bin/picoclaw /usr/local/bin/picoclaw
 
 # Create non-root user and group
 RUN addgroup -g 1000 picoclaw && \

Makefile

@@ -3,7 +3,7 @@
 
 # Build variables
 BINARY_NAME=picoclaw
-BUILD_DIR=build
+BUILD_DIR=bin
 CMD_DIR=cmd/$(BINARY_NAME)
 MAIN_GO=$(CMD_DIR)/main.go
 

README.md

@@ -164,7 +164,7 @@ make build
 
 ```bash
 # Initialize config and workspace
-./build/picoclaw onboard
+./bin/picoclaw onboard
 ```
 
 Edit `~/.picoclaw/config.json`: