release: v2.9.0 — agent-browser, manifest reader, opencode 1.18.13

Not tagged yet; this is the v2.9.0 changeset landing on main.

Added
- agent-browser + a Playwright-managed headless Chromium in the base (~625 MB
  after deleting the redundant chromium_headless_shell build), so an agent can
  drive a real browser and VERIFY front-end work instead of assuming it renders.
  Ported from pi-devbox. AGENT_BROWSER_EXECUTABLE_PATH points at the stable
  symlink /usr/local/bin/agent-chrome, which the Dockerfile resolves with `find`
  rather than hardcoding: Playwright's browser dir is per-version AND per-arch
  (chrome-linux on arm64, chrome-linux64 on amd64), and the headless shell binary
  is named chrome-headless-shell so `-name chrome` skips it.
- opencode-devbox-version: a reader for the build manifest. The image has baked
  ground truth to /etc/opencode-devbox/build-manifest.json for several releases,
  but nothing read it and nothing printed it — so "which image am I running?"
  meant knowing the path by heart. Three modes (--json/--quiet/human), plus a
  live-vs-baked drift check, because NPM_CONFIG_PREFIX points at the persistent
  config volume and a user `npm install -g opencode` can shadow the baked binary.
  entrypoint-user.sh prints it as its first output.
- ENV COLORTERM=truecolor, completing a true-colour story the image already
  half-shipped (terminfo entries + Neovim termguicolors, but no capability
  advertisement, so bat/delta fell back to 256 colours).
- Smoke assertions for agent-browser, that agent-chrome resolves to an
  executable (catches a Playwright layout change, not just a dangling symlink),
  COLORTERM, the manifest's release_tag, and all three version-command modes.

Changed
- opencode 1.17.20 -> 1.18.13. Verified by diffing upstream source, not release
  notes: core config.ts, config/provider.ts and schema.json are byte-identical,
  so generate-config.py needs no change. 1.18.13 (published mid-audit) was
  re-verified separately — 249 files in the compare payload, under GitHub's
  300-file cap, so the list is complete rather than truncated; content is the
  Electron app plus localisation; the five contract-surface files hash identical
  at both tags. The bg-subagents removal trigger has NOT fired: runtime-flags.ts
  still gates the flag behind OPENCODE_EXPERIMENTAL at all three tags.
- yq: dropped Debian's apt package (the unrelated Python kislyuk/yq — jq syntax,
  3.x line) for mikefarah's Go yq v4 from GitHub. The cloud-init repo's
  provision.sh/deploy.sh need v4 syntax, and THIRD_PARTY.md already credited
  "yq (mikefarah)" while the image shipped the Python one, so this also closes a
  documented-vs-shipped mismatch. Smoke pins the contract to mikefarah v4.
  BEHAVIOUR CHANGE for any in-image script calling yq with jq-style syntax.
- mempalace pin 3.5.0 -> 3.6.0, in lockstep with pi-devbox (5724302). Reviewed
  for MCP tool-schema changes before bumping — none, and nothing touches
  diary_write.
- Default models -> claude-opus-5 (anthropic, and bedrock's
  global.anthropic.claude-opus-5) and openai/gpt-5.6. gpt-5.4 had gone stale:
  gpt-5.6 shipped four days before the v2.8.0 cut. Affects only new containers
  with no OPENCODE_MODEL and no existing config.
- Smoke size thresholds +650 MB (base 2950->3600, omos 3650->4300), sized to
  keep the same ~250 MB headroom so the guardrail still catches runaway growth
  rather than routine apt drift. Do NOT copy pi-devbox's number: it sums
  `docker history`, this repo uses `docker image inspect .Size`.

Documentation
- New README section "Choosing a provider and model", making explicit that the
  baked defaults are only defaults and nobody is locked to Anthropic/Bedrock,
  including the three real gotchas: defaults seed only a NEW config, an existing
  opencode.jsonc on the persistent volume is never rewritten, and switching
  model needs no rebuild.
- New README section "Browser automation (agent-browser)"; opencode-devbox-version
  documented under Build provenance; COLORTERM under Terminal compatibility.
- README Build Args table drift fixed — FOUR missing args added
  (AGENT_BROWSER_VERSION, PLAYWRIGHT_VERSION, YQ_VERSION and GITLEAKS_VERSION,
  the last of which had existed as an ARG but was never listed), plus rows for
  the two pinned args absent entirely (MEMPALACE_VERSION, DEBIAN_VERSION), plus
  a refreshed stale OPENCODE_VERSION example. Third consecutive release to find
  drift in this table.
- AGENTS.md: the stale MemPalace anyOf convention rewritten. It described a perl
  RUN block already DELETED at the 3.5.0 bump and asserted "PyPI latest is 3.4.0
  (== our pin), no release contains the fix yet, the workaround must stay" — all
  three false. Replaced with a pin-review rule. Two new conventions added: the
  agent-browser/Chromium size coupling, and the yq identity trap.
- THIRD_PARTY.md: agent-browser, Playwright, Chromium.

Verified locally with the CI-pinned hadolint 2.14.0 and actionlint 1.7.7, the
shell guard, DOCKER_HUB.md sync, bash -n, py_compile, and by generating the
config for all three providers.

scripts/smoke-test.sh

@@ -139,7 +139,13 @@ run "fzf"               "fzf --version"
 run "fd"                "fd --version"
 run "rg"                "rg --version | head -1"
 run "jq"                "jq --version"
-run "yq"                "yq --version"
+# yq MUST be mikefarah's Go yq v4, NOT Debian's `yq` apt package (the unrelated
+# Python kislyuk/yq — a jq wrapper on a 3.x line with incompatible syntax). v2.9.0
+# swapped the apt package for the mikefarah binary. Pinning the contract to major
+# v4 makes BOTH a regression to the Python package AND a surprise future yq v5
+# fail CI loudly, instead of silently breaking the cloud-init repo's
+# provision.sh/deploy.sh which require v4 syntax.
+run "yq is mikefarah v4"  "yq --version | grep -qE 'mikefarah.*version v4' && yq --version"
 run "git-crypt"         "git-crypt --version | head -1"
 run "gitleaks"          "gitleaks version"
 run "aws"               "aws --version"
@@ -148,6 +154,17 @@ run "gosu"              "gosu --version"
 run "tmux"              "tmux -V"
 run "pandoc"            "pandoc --version | head -1"
 run "typst"             "typst --version"
+# agent-browser + its Chromium. The ENV must point at a resolvable executable:
+# AGENT_BROWSER_EXECUTABLE_PATH -> /usr/local/bin/agent-chrome -> Playwright's
+# per-version, per-ARCH chrome binary. Asserting the resolved target is
+# executable catches a Playwright layout change (the reason the Dockerfile
+# `find`s the binary instead of hardcoding the path) rather than just checking
+# that a dangling symlink exists.
+run "agent-browser"      "agent-browser --version"
+run "agent-chrome resolves to an executable" \
+    "test -x \"\$(readlink -f /usr/local/bin/agent-chrome)\" && readlink -f /usr/local/bin/agent-chrome"
+run_expect "AGENT_BROWSER_EXECUTABLE_PATH baked" \
+    "printenv AGENT_BROWSER_EXECUTABLE_PATH" "/usr/local/bin/agent-chrome"
 run "pandoc+typst PDF engine" "printf '# hi\n' | pandoc --pdf-engine=typst -o /tmp/_smoke.pdf - && test -s /tmp/_smoke.pdf; rm -f /tmp/_smoke.pdf"
 run "graphviz (dot)"    "dot -V"
 run "tldr (tealdeer)"   "tldr --version"
@@ -157,6 +174,9 @@ run "dot-watch"         "test -x /usr/local/bin/dot-watch && bash -n /usr/local/
 # and OMOS V2+ default orchestration depends on it. Baked ON as an ENV in
 # Dockerfile.base — assert it's present in the image environment (both variants).
 run_expect "bg-subagents env baked" "printenv OPENCODE_EXPERIMENTAL_BACKGROUND_SUBAGENTS" "true"
+# True-colour advertisement for colour-aware tools (bat, delta, Neovim's
+# auto-detect). Pairs with the terminfo entries + sysinit.vim termguicolors.
+run_expect "COLORTERM env baked" "printenv COLORTERM" "truecolor"
 
 # SSH ControlMaster baked defaults: the config file must exist (image-level)
 # and ssh -G must report ControlPath rooted at /tmp/sshcm/ for an arbitrary
@@ -242,6 +262,17 @@ run_expect "manifest records opencode_version" \
     "cat /etc/opencode-devbox/build-manifest.json" '"opencode_version"'
 run_expect "manifest records mempalace-toolkit component" \
     "cat /etc/opencode-devbox/build-manifest.json" '"mempalace-toolkit"'
+run_expect "manifest records release_tag" \
+    "cat /etc/opencode-devbox/build-manifest.json" '"release_tag"'
+# The manifest is only useful if something can READ it. v2.9.0 added
+# opencode-devbox-version as that reader (and entrypoint-user.sh prints it at
+# container start), so assert the command itself works in all three modes —
+# otherwise the manifest stays an invisible artifact, which is what it was for
+# every release before this one.
+run_expect "opencode-devbox-version --json emits the manifest" \
+    "opencode-devbox-version --json" '"release_tag"'
+run "opencode-devbox-version --quiet" "opencode-devbox-version --quiet"
+run "opencode-devbox-version (human)" "opencode-devbox-version | head -1"
 # Every resolved component must be a real value, never the 'unknown'
 # sentinel that rev()/version lookups emit on failure. (oh-my-opencode-slim
 # is JSON null in the base variant — that is expected, not 'unknown'.)
@@ -403,8 +434,17 @@ echo "  Uncompressed size: ${SIZE_MB} MB"
 # headroom keeps the guardrail catching *runaway* growth (accidental texlive/
 # chrome bake-in) rather than tripping on routine apt drift or a minor opencode
 # bump. smoke still prints the actual landed size each run; tighten if low.
-THRESHOLD=2950
-[ "$VARIANT" = "omos" ] && THRESHOLD=3650
+# v2.9.0: bumped +650 MB (2950->3600 base, 3650->4300 omos) for agent-browser +
+# Playwright Chromium on the BASE layer (~625 MB after dropping the redundant
+# chromium_headless_shell build). Sized to keep roughly the same ~250 MB of
+# headroom the previous thresholds had, so the guardrail still catches *runaway*
+# growth (an accidental texlive or a second browser) rather than tripping on
+# routine apt drift. NOTE: do NOT copy pi-devbox's threshold number across — it
+# sums `docker history` while this script uses `docker image inspect .Size`, so
+# the two are not directly comparable. smoke prints the actual landed size every
+# run; tighten these if they come in low.
+THRESHOLD=3600
+[ "$VARIANT" = "omos" ] && THRESHOLD=4300
 if [ "$SIZE_MB" -gt "$THRESHOLD" ]; then
   fail "image size ${SIZE_MB} MB exceeds threshold ${THRESHOLD} MB for variant=$VARIANT"
 else