add Dockerfile and Rocky Linux 9 build docs

Introduces a Docker-based build path so ior can be compiled on any
Linux host without a native Rocky 9 toolchain setup:

- Dockerfile: Rocky 9 minimal image with Go (version from ARG, default
  from go.mod), static libelf/libzstd built from source, libbpfgo at
  v0.9.2-libbpf-1.5.1, and mage; CMD runs mage generate + mage all
  against the repo root mounted as a volume.
- scripts/build-with-docker.sh: reads GO_VERSION from go.mod, passes it
  as --build-arg to docker build, mounts tracefs and BTF into the
  container, writes the binary to the repo root.
- Magefile.go: adds BuildDocker target that wraps the script.
- README.md: simplified to the two build paths (Docker + native) with
  links to docs/; removed GOTOOLCHAIN=auto throughout.
- docs/build-rocky-linux-9.md: full manual Rocky 9 steps, libbpfgo
  toolchain setup/rollback, compile-once-run-everywhere explanation,
  and timing semantics.
- docs/tui-reference.md: complete TUI hotkey reference, recording mode
  details, and the .ior.zst vs Parquet trade-off table.
- AGENTS.md: removed GOTOOLCHAIN=auto from all build commands.
- internal/c/generated_tracepoints.c: regenerated against the host kernel.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

1 files changed, 14 insertions, 13 deletions

diff --git a/AGENTS.md b/AGENTS.md
index 0d65300..11a3618 100644
--- a/AGENTS.md
+++ b/AGENTS.md
@@ -12,22 +12,23 @@ git -C ../libbpfgo submodule update --init --recursive
 make -C ../libbpfgo libbpfgo-static
 ```
 
-If builds/tests fail with missing libbpf headers (for example `bpf/bpf.h` not found), rerun the commands above and then run `env GOTOOLCHAIN=auto mage world`. Prefer Mage targets over raw `go test` for packages that import `libbpfgo`; Mage wires the required `CGO_CFLAGS`, `CGO_LDFLAGS`, and `LIBBPFGO` values.
+If builds/tests fail with missing libbpf headers (for example `bpf/bpf.h` not found), rerun the commands above and then run `mage world`. Prefer Mage targets over raw `go test` for packages that import `libbpfgo`; Mage wires the required `CGO_CFLAGS`, `CGO_LDFLAGS`, and `LIBBPFGO` values.
 
 ```bash
-env GOTOOLCHAIN=auto mage all          # Build everything (BPF objects and Go binary)
-env GOTOOLCHAIN=auto mage test         # Run all tests
-GOTOOLCHAIN=auto TEST_NAME=TestEventloop mage testWithName  # Run specific test
-env GOTOOLCHAIN=auto mage integrationTest  # Build + run integration tests (default parallelism is capped)
-GOTOOLCHAIN=auto INTEGRATION_PARALLEL=1 mage integrationTest  # Force serial integration tests
-env GOTOOLCHAIN=auto mage generate     # Generate code (required after modifying tracepoint definitions)
-env GOTOOLCHAIN=auto mage bench        # Run benchmarks
-env GOTOOLCHAIN=auto mage prReview     # Run PR review baseline: world + benchProf
-env GOTOOLCHAIN=auto mage clean        # Clean build artifacts
-env GOTOOLCHAIN=auto mage world        # Clean + generate + test + build (recommended reset path)
-env GOTOOLCHAIN=auto mage demo         # Regen demo/ GIFs + screenshots (needs vhs+ttyd, sudo -v warmed)
+mage all          # Build everything (BPF objects and Go binary)
+mage buildDocker                       # Build ior inside a Rocky Linux 9 container (writes binary to repo root)
+mage test         # Run all tests
+TEST_NAME=TestEventloop mage testWithName  # Run specific test
+mage integrationTest  # Build + run integration tests (default parallelism is capped)
+INTEGRATION_PARALLEL=1 mage integrationTest  # Force serial integration tests
+mage generate     # Generate code (required after modifying tracepoint definitions)
+mage bench        # Run benchmarks
+mage prReview     # Run PR review baseline: world + benchProf
+mage clean        # Clean build artifacts
+mage world        # Clean + generate + test + build (recommended reset path)
+mage demo         # Regen demo/ GIFs + screenshots (needs vhs+ttyd, sudo -v warmed)
 TAPE=07-stream-live mage demoOne       # Regen one demo tape only
-env GOTOOLCHAIN=auto mage installDemoTools  # One-time: install vhs (go install) and ttyd (dnf)
+mage installDemoTools  # One-time: install vhs (go install) and ttyd (dnf)
 ```
 
 ## Demo Pipeline