v1.0.0: decouple from opencode-devbox

Self-contained build chain — own Dockerfile.base + Dockerfile.variant
+ entrypoint scripts + rootfs + CI pipeline. Previously v0.79.0 and
earlier were thin re-brands of opencode-devbox's pi-only variant
(joakimp/pi-devbox:base-pi-only built by opencode-devbox CI).

Architectural changes:
- Replace 5-line Dockerfile shim with full base+variant pair.
- Adapt CI workflow from opencode-devbox/docker-publish-split.yml,
  simplified to a single variant. Includes content-addressed base hash,
  PI_VERSION concrete-resolution to defeat registry-buildcache footgun,
  crane-based base-latest promotion, and the c6f9d11 smoke-test gate.
- pi-devbox releases no longer require rebuilding opencode-devbox first.

Base image additions:
- pandoc, graphviz, imagemagick, yq — broadly useful, ~260 MB total.
- tldr (tealdeer) — Rust port replaces Node tldr global, saves 135 MB.
- /etc/tmux.conf with base-index 0 + pane-base-index 0 — required for
  the planned :latest-studio variant; pi-studio hard-codes :0.0 target.

Smoke test:
- New checks for pandoc, graphviz, imagemagick, yq, tldr, tmux config,
  /tmp/sshcm directory.
- Image-size measurement now sums docker history layers (the prior
  inspect --format='{{.Size}}' returned only the variant-unique layer
  with the new base/variant split, understating by 2+ GB).
- Threshold 2850 → 3500 MB to absorb base additions + arch margin.

Image size:
- Local arm64 build: 3.20 GB. ~390 MB up from prior pi-only equivalent.
- Will tighten threshold once amd64 actuals settle in CI.

Pre-1.0 history preserved at tag pre-v1.0.0-decouple-backup.

Future work:
- v1.1.0: :latest-studio variant (adds pi-studio).
- v1.2.0: :latest-studio-tex variant (adds texlive-xetex for PDF).
- opencode-devbox v2.0.0 will retire INSTALL_PI / pi-only paths.

CHANGELOG.md

@@ -2,13 +2,96 @@
 
 All notable changes to the pi-devbox container image.
 
-Tags follow the pi npm version: `v{pi_version}[letter]` — bare tag for the first build on a new pi release, letter suffix (`b`, `c`, …) for container-level rebuilds on the same version.
+From v1.0.0 onward, tags follow semver:
+- **major** — architectural changes (v1.0.0 = decoupled from opencode-devbox)
+- **minor** — new variants, significant base additions
+- **patch** — pi version bumps, smaller fixes
+
+Pre-v1.0.0 tags followed the pi npm version (`v{pi_version}[letter]`).
 
 ---
 
 ## Unreleased
 
-_(no changes since v0.79.0)_
+_(no changes since v1.0.0)_
+
+## v1.0.0 — 2026-06-09
+
+**Decoupled from opencode-devbox.** pi-devbox is now self-contained:
+own `Dockerfile.base` + `Dockerfile.variant`, own CI pipeline, own
+release cadence. Previously v0.79.0 and earlier were thin re-brands of
+the `pi-only` variant built by opencode-devbox CI.
+
+### Architectural
+
+- **Self-contained build chain.** `Dockerfile.base` produces
+  `joakimp/pi-devbox:base-<hash>` (content-addressed); `Dockerfile.variant`
+  FROMs the base and adds the pi install. Replaces the prior 5-line
+  `Dockerfile` shim that FROMed `joakimp/pi-devbox:base-pi-only` (an
+  opencode-devbox CI artifact).
+- **No more publish-ordering coupling.** pi-devbox releases no longer
+  require rebuilding opencode-devbox first.
+- **Adapted from opencode-devbox** at the time of decoupling — the
+  apt set, ssh ControlMaster setup, MemPalace integration, entrypoint
+  UID/GID dance, and CI pipeline shape are all derived from there. See
+  Acknowledgements in README.md.
+- **CI workflow** rewritten as two-phase split-base build pipeline
+  (mirrors opencode-devbox's `docker-publish-split.yml` shape, simplified
+  to a single variant). Includes `crane`-based `base-latest` promotion,
+  registry-buildcache footgun guard via concrete `PI_VERSION` resolution,
+  and the c6f9d11 smoke-test gate (waits for keybindings + mempalace.ts
+  + ≥4 *.ts before sampling).
+
+### Added (base image)
+
+- **pandoc** — universal Markdown↔HTML/Org/RST/etc. conversion. ~200 MB.
+- **graphviz** — `dot` rendering for diagram pipelines. ~10 MB.
+- **imagemagick** — image conversion (invoked as `magick`, not `convert`,
+  in v7+). ~50 MB.
+- **yq** — YAML-aware companion to jq.
+- **tldr (tealdeer)** — Rust port of tldr-pages, ~5 MB static binary.
+  Replaced the Node `tldr` global (which was ~140 MB).
+- **`/etc/tmux.conf`** with `set -g base-index 0` + `set -g
+  pane-base-index 0`. Required for the planned `:latest-studio`
+  variant; pi-studio hard-codes its tmux send target to `:0.0`. User-
+  level `~/.tmux.conf` overrides still win.
+
+### Added (smoke test)
+
+- Asserts pandoc, graphviz, imagemagick, yq, and tldr are present.
+- Asserts `/etc/tmux.conf` has the 0-indexed config baked.
+- Asserts `/tmp/sshcm/` directory created mode 700 by entrypoint.
+- Image-size measurement now sums `docker history` layer sizes (the
+  prior `image inspect --format='{{.Size}}'` approach returned only
+  the variant-unique layer when the base was content-addressed and
+  shared, understating the user-facing image size by 2+ GB).
+- Size threshold raised to 3500 MB (was 2850) to cover the new base
+  additions plus +200 MB safety margin. Tighten in a follow-up release
+  once amd64 actuals settle.
+
+### Image size
+
+Local arm64 build of `pi-devbox-test:latest` (this branch's content):
+3.20 GB. Up ~390 MB from the prior pi-only-equivalent (~2.81 GB) due
+to pandoc, graphviz, imagemagick, yq, and minor expansion in pi npm
+dependencies.
+
+### Migration notes
+
+- Existing volumes (`devbox-pi-config`, `devbox-bash-history`,
+  `devbox-nvim-data`, `devbox-uv-tools`, `devbox-chroma-cache`) are
+  unchanged in name and structure. `docker compose pull && docker
+  compose up -d --force-recreate` is a clean upgrade path.
+- The `:latest` and `vX.Y.Z` Hub tags continue to point at a "base +
+  pi" image. Same shape, just built differently.
+- `:base-pi-only` and `:base-pi-only-vX.Y.Z` tags from prior releases
+  remain on Hub for now; will be deprecated when opencode-devbox
+  retires the pi paths in its next major release.
+
+### Future work
+
+- v1.1.0: `:latest-studio` variant (adds [pi-studio](https://github.com/omaclaren/pi-studio)).
+- v1.2.0: `:latest-studio-tex` variant (adds texlive-xetex for PDF export).
 
 ## v0.79.0 — 2026-06-08