Move build output from src/build/ to ./build (repo root)

The build directory was under src/, which is unusual for a project
with a separate source tree. Moving it to the repo root's build/
directory follows the conventional project layout:

  ./build/           # build output (gitignored)
  ./src/             # source code only
  ./oscar64/         # compiler (submodule)

Changes:
- src/build.sh: BUILD_DIR changed from $SCRIPT_DIR/build to
  $ROOT/build
- .gitignore: replaced src/build/ with build/
- README.md: updated layout tree, build commands, and output path
- src/AGENT_CONTEXT.md: updated gitignore reference
- tasks.md: replaced all src/build/ with build/

.gitignore

@@ -1,5 +1,5 @@
 # build artifacts
-src/build/
+build/
 *.prg
 *.asm
 *.map

README.md

@@ -9,6 +9,7 @@ as the cross-compiler. Oscar64 is checked in as a git submodule under
 ```
 .
 ├── oscar64/        # Oscar64 cross-compiler (git submodule)
+├── build/          # Build output (gitignored)
 ├── docs/c64/       # Low-level C64 reference (memory map, VIC, CIA, SID, …)
 ├── src/            # Your C code
 │   ├── helloworld.c
@@ -31,11 +32,14 @@ git submodule update --init --recursive
 
 ```sh
 cd src
-./build.sh            # compile helloworld.c → src/build/helloworld.prg
+./build.sh            # compile main.c → build/whack_hare.prg (-O1)
 ./build.sh -e         # run in oscar64's built-in emulator (headless, fast)
-./build.sh -v         # run in VICE x64 (interactive, needs a real display)
-./build.sh -V         # run in VICE x64sc (interactive, cycle-exact)
+./build.sh -p         # PLAY: launch VICE in background (see build.sh --help)
+./build.sh -v         # run in VICE x64 (foreground, blocks terminal)
+./build.sh -V         # run in VICE x64sc (cycle-exact, foreground)
+./build.sh --kill     # kill any detached VICE process
 ./build.sh -c         # just compile
+./build.sh -O3        # release build (auto-ZP, outliner, aggressive inlining)
 ```
 
 `build.sh` will build the oscar64 compiler automatically the first time

src/AGENT_CONTEXT.md

@@ -155,7 +155,7 @@ $21-$24) goes to $D800-$DBE7.
 ## Commit conventions
 
 - One commit per phase, with a clear `Phase N: <summary>` prefix.
-- Don't commit generated build artifacts in `src/build/` (gitignored).
+- Don't commit generated build artifacts in `build/` (gitignored).
 - Generated data files (e.g. `src/data/processed/*.bin`) are checked
   in so the build doesn't depend on Python being installed.
 

src/build.sh

@@ -16,7 +16,7 @@
 #   ./build.sh -Os        # compile with -Os (optimize for size)
 #   ./build.sh -g         # compile with -g (adds source-level debug info)
 #
-# Output (in ./build/):
+# Output (in <repo>/build/):
 #   whack_hare.prg   — loadable C64 program (run with x64, VICE, or real hw)
 #   whack_hare.asm   — full 6502 listing
 #   whack_hare.map   — region/section/object placement
@@ -47,7 +47,7 @@ SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)"
 ROOT="$(cd "$SCRIPT_DIR/.." && pwd)"
 OSCAR64_DIR="$ROOT/oscar64"
 OSCAR64_BIN="$OSCAR64_DIR/bin/oscar64"
-BUILD_DIR="$SCRIPT_DIR/build"
+BUILD_DIR="$ROOT/build"
 PRG="$BUILD_DIR/whack_hare.prg"
 D64="$BUILD_DIR/whack.d64"
 

tasks.md

@@ -65,15 +65,15 @@ runs.
 
 - [x] ✅ Repo initialized, oscar64 is a submodule at `./oscar64/`.
 - [x] ✅ `src/helloworld.c` + `src/build.sh` produce
-  `src/build/helloworld.prg`.
+  `build/helloworld.prg`.
 - [x] ✅ `GAME.md` written.
 - [x] ✅ Source artwork in `./source_images/`.
 - [ ] ⏳ **Verify:** `cd src && ./build.sh -e` runs the hello-world
   program in the oscar64 built-in emulator. (Optional: launch
-  `x64 src/build/helloworld.prg` in a real terminal session
+  `x64 build/helloworld.prg` in a real terminal session
   to see the screen.)
 
-**Done means:** `src/build/helloworld.prg` exists and the
+**Done means:** `build/helloworld.prg` exists and the
 emulator prints "Hello World" then exits cleanly.
 
 ---
@@ -171,7 +171,7 @@ state.
 - `cd src && ./build.sh -e` displays the title screen in the
   oscar64 built-in emulator for 5 seconds (or until fire is pressed)
   then exits.
-- (Optional, interactive) `x64 src/build/whack_hare.prg` in a real
+- (Optional, interactive) `x64 build/whack_hare.prg` in a real
   terminal session displays the title screen on real timings.
   Compare visually to `source_images/screen_title.png`.
 - The .map file shows our code is in $0900-$1100-ish, well within
@@ -304,7 +304,7 @@ random source.
 **Verify:**
 - The game still works in the oscar64 built-in emulator
   (`build.sh -e`).
-- (Optional, interactive) Launch `x64sc src/build/whack_hare.prg`
+- (Optional, interactive) Launch `x64sc build/whack_hare.prg`
   in a real terminal to confirm the game runs at cycle-exact PAL
   timing (50.125 Hz). The state transitions happen on the right
   raster lines. The 50 Hz tick is rock-solid.
@@ -363,7 +363,7 @@ becomes audible.
   - GAMEOVER: longer fanfare.
 - The cues are recognizable and feel right (timing, volume).
 - (Optional, interactive) Run the audio cues under `x64sc
-  src/build/whack_hare.prg` in a real terminal to confirm the
+  build/whack_hare.prg` in a real terminal to confirm the
   SID envelope generator timings are right; the oscar64 emulator
   is fast but not always bit-accurate on SID timing, and the
   `x64sc` cycle-exact path is the one that matches real hardware.