pipeline: share a single compile function across CLI, bench, and tests

The compile bench had a hand-maintained parallel copy of
`src/main.rs::compile`, and that copy went out of sync after
bank switching landed — the bench kept handing the linker
`PrgBank::empty(...)` slots even though the CLI started
populating per-bank instruction streams + trampoline requests.
The assembler then panicked with `unresolved label:
'__tramp_step_animation'` on `uxrom_user_banked.ne` under
`cargo test --all-targets`, which is what CI runs. A plain
`cargo test --release` (what CLAUDE.md used to document) never
builds the bench so the bug slipped through local validation.

Fix:

- New `nescript::pipeline` module with `compile_source(source,
  source_dir, &CompileOptions)` that owns the full
  `parse → analyze → lower → optimize → codegen → peephole →
  link` pipeline including the per-bank stream + trampoline
  reconstruction. Returns a `CompileOutput` carrying the ROM,
  the linker result, analysis, IR, assets, instructions, and
  source-loc markers so downstream tools have one place to
  pull metadata from.
- `src/main.rs::compile` reduces to file I/O + preprocessing +
  a single `compile_source` call + CLI-only side effects
  (`--dump-ir`, `--call-graph`, `--asm-dump`, `--memory-map`,
  `--symbols`, `--source-map`).
- `benches/compile.rs::compile_pipeline` becomes a one-line
  `compile_source` call. It is now structurally impossible for
  the bench to drift from the CLI path.
- `tests/integration_test.rs::compile_with_debug_artifacts`
  likewise delegates to `compile_source`. This also fixes a
  latent bug in the helper where it used `Linker::with_mapper`
  without `.with_header(...)` — programs opting into
  `header: nes2` would have quietly got an iNES 1.0 header
  through this path.
- `CLAUDE.md`: updated the "Running the basics" section to
  specify `cargo test --all-targets` (plain `cargo test` skips
  benches) and to point at `scripts/pre-commit` with the exact
  install command. Also installed the hook in this worktree.

All 24 existing `examples/*.nes` rebuild byte-identical through
the new pipeline. 624 tests + all 25 emulator goldens pass.

https://claude.ai/code/session_01MaNVcDmK9gsspRkdxowQAM

CLAUDE.md

@@ -44,13 +44,32 @@ re-derive the project conventions from scratch.
 ## Running the basics
 
 ```bash
-cargo build --release          # build the compiler
-cargo test                     # all Rust tests (lib + integration)
-cargo fmt                      # mandatory before committing
-cargo clippy --all-targets     # mandatory before committing; fix or #[allow]
+cargo build --release              # build the compiler
+cargo test --all-targets           # all Rust tests — MUST include --all-targets
+cargo fmt                          # mandatory before committing
+cargo clippy --all-targets -- -D warnings   # mandatory; fix or #[allow]
 ./target/release/nescript build examples/hello_sprite.ne   # build one ROM
 ```
 
+**Always pass `--all-targets` to `cargo test`.** CI runs `cargo test
+--all-targets`, which additionally compiles and smoke-runs the `compile`
+benchmark under `benches/compile.rs`. A plain `cargo test` skips that,
+so a bench that doesn't compile will pass locally and red-flag CI —
+this exact failure mode bit us once already (commit `889074a`).
+
+The repo ships a pre-commit hook at `scripts/pre-commit` that runs
+`cargo fmt --check`, `cargo clippy --all-targets -- -D warnings`,
+`cargo test --all-targets`, and the committed-ROM reproducibility diff.
+Install it once per worktree with:
+
+```bash
+cp scripts/pre-commit .git/hooks/pre-commit && chmod +x .git/hooks/pre-commit
+```
+
+Do this before your first commit in a new worktree. The hook catches
+stale ROMs, stale platformer gif, and divergent bench/compile pipelines
+before they hit CI.
+
 Compile every example at once:
 
 ```bash