Stop Playwright setup from deleting the package it just installed

Setting up the browser view failed on every container, and re-running it
reproduced the same broken state, because the setup destroyed its own work.

`install_packages` ran two `npm install --no-save` commands into
/workspace, which has no package.json. With no manifest, npm treats the
command line as the whole statement of what the tree should contain and
prunes the rest, so installing `playwright` second removed the
`@playwright/cli` installed first: "removed 3 packages", leaving an empty
node_modules/@playwright/ behind playwright and playwright-core. That
empty directory is exactly what the pane then reported as missing. The
second install now names both specs; the first one is already present, so
it costs nothing and is only there to stop npm pruning it.

Two failures were waiting behind that one:

Nothing in the tree ever configured the browser, so playwright-cli fell
back to channel `chrome` — system Google Chrome — with the Chromium
sandbox on. These containers forbid unprivileged user namespaces, so it
aborted with "Failed to move to new namespace ... Operation not
permitted"; on a base image without Google Chrome the same default failed
as "Chromium distribution 'chrome' is not found". entrypoint.sh now seeds
~/.playwright/cli.config.json on every start, which is the only way to
reach existing projects: ~/.playwright is inside the home volume, so an
image copy would reach new projects only.

The launch check passed for a configuration the viewer never uses. It
launched bundled chromium with no channel, which resolves to
chromium-headless-shell, while the viewer's config pins
chrome-for-testing — the full chromium build, a separate download. A
container could pass every check and still fail in the pane with 'Browser
"chrome-for-testing" is not installed', which is what a stale
chromium-1217 against a wanted chromium-1237 did. Chromium is now
verified on both channels, the sandbox setting is stated rather than
inherited from a default, and a failure names the channel.

triple-c-playwright-heal repairs all of it on a container that is already
broken, including the missing socat that makes the pane report
"127.0.0.1 sent an invalid response" while the container side is
perfectly healthy. It verifies by launching a browser rather than
trusting the preceding steps — which is how the stale-revision case was
found — and lives in /usr/local/bin so a fix to it can still reach an
existing project.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

container/entrypoint.sh

@@ -425,6 +425,32 @@ if [ -x /usr/local/bin/triple-c-open ]; then
     export BROWSER=/usr/local/bin/triple-c-open
 fi
 
+# ── Playwright browser config ───────────────────────────────────────────────
+# Seed ~/.playwright/cli.config.json on every start.
+#
+# Without it `playwright-cli` resolves to channel `chrome` — system Google
+# Chrome — with the Chromium sandbox ON, and these containers do not permit
+# unprivileged user namespaces, so the browser aborts with "Failed to move to
+# new namespace ... Operation not permitted". On a base image that no longer
+# ships Google Chrome the same default fails the other way, with "Chromium
+# distribution 'chrome' is not found". One cause, two error messages, and
+# neither of them looks like a configuration problem.
+#
+# Seeded here rather than baked into the image because ~/.playwright is inside
+# the home volume: an image copy would reach new projects only, and every
+# existing project would stay broken forever. Written on every start from a
+# source outside the volume, the way CLAUDE_INSTRUCTIONS and the Mission
+# Control skills already are.
+#
+# --seed-config-only is the cheap path: no npm install, no browser download, no
+# apt, no verify launch, nothing over the network. It writes one small file if
+# it is absent and returns. Measured at ~2 ms. The heavier repairs stay
+# on-demand — run `triple-c-playwright-heal` with no arguments for those.
+if [ -x /usr/local/bin/triple-c-playwright-heal ]; then
+    /usr/local/bin/triple-c-playwright-heal --seed-config-only --quiet || \
+        echo "entrypoint: warning — playwright config seeding failed (browser view may not launch)"
+fi
+
 # ── Scheduler setup ─────────────────────────────────────────────────────────
 SCHEDULER_DIR="/home/claude/.claude/scheduler"
 mkdir -p "$SCHEDULER_DIR/tasks" "$SCHEDULER_DIR/logs" "$SCHEDULER_DIR/notifications"