chore: remove unused surfaces (VS Code extension, statusline, landing assets, Docker)

The repo shipped five install/publish surfaces that nothing in the project builds, tests or documents as supported any more. Each one carried its own stale docs, and the Docker/Podman path additionally described a Dockerfile whose COPY of statusline/ would have broken the build the moment that directory went away.

Removed: vscode-extension/ (16 files, marketplace extension for an ID we do not own); statusline/ (3 files, standalone CLI statusline); the repo-root landing/wiki PWA assets (sw.js, manifest.json, robots.txt, sitemap.xml, og-image.svg, favicon.svg, fonts/ - 17 files for pages that no longer exist); .superpowers/ (4 files of scratch brainstorm state, already covered by .gitignore:55); and the container publish path (Dockerfile, docker-compose.yml, .dockerignore, 5 Makefile targets, 2 npm scripts).

Kept deliberately - these are about the USER's containers, not ours: scripts/install-hooks.js container detection and AGENTHUB_ALLOW_CONTAINER_HOOKS (issue #193), server/lib/lane-detect.js docker-compose service detection, server/data/profile-templates/postgres-compose/, server/lib/stage-detect.js 'docker push' detection, the host.docker.internal Prometheus notes, the Config Explorer's reads of the user's own ~/.claude/statusline.py, and .devcontainer/ (its docker-in-docker feature is dropped since it existed only to build the removed Dockerfile).

Docs follow the code: ARCHITECTURE.md loses the VS Code, statusline and container sections plus two dead TOC anchors, and its PWA section is rewritten from three PWAs to one; INSTALL.md, SETUP.md, docs/DEPLOYMENT.md, server/README.md, client/README.md, docs/README.md, docs/HOOKS.md and docs/DATABASE.md drop the same. The Makefile target count in ARCHITECTURE.md is corrected 25 -> 17 (it was already stale).

.devcontainer/devcontainer.json

@@ -4,9 +4,9 @@
   // Used only when you choose "Dev Containers: Reopen in Container" (VS Code) or
   // open the repo in a GitHub Codespace. It changes nothing for host-based dev.
   //
-  // Covers the full project: the Express server (4820), the React/Vite client
-  // (5173) and the VS Code extension. The native `better-sqlite3`
-  // addon builds here (build-essential + python3 are installed in the Dockerfile).
+  // Covers the full project: the Express server (4820) and the React/Vite
+  // client (5173). The native `better-sqlite3` addon builds here
+  // (build-essential + python3 are installed in the Dockerfile).
   //
   // NOTE (issue #193): Claude Code hooks are a HOST-side concern. This container
   // intentionally does NOT bind-mount ~/.claude and does NOT install hooks — the
@@ -20,10 +20,7 @@
   },
 
   "features": {
-    "ghcr.io/devcontainers/features/github-cli:1": {},
-    // Lets you build/run the project's own production Dockerfile + docker-compose
-    // from inside the dev container (e.g. to reproduce issue #193 deliberately).
-    "ghcr.io/devcontainers/features/docker-in-docker:2": {}
+    "ghcr.io/devcontainers/features/github-cli:1": {}
   },
 
   // Server (API + WebSocket) and the Vite client dev server. VS Code forwards
@@ -40,7 +37,7 @@
     }
   },
 
-  // Install root + client + vscode-extension deps.
+  // Install root + client deps.
   // Never installs Claude Code hooks (host-only — see note above).
   "postCreateCommand": "bash .devcontainer/post-create.sh",
   "waitFor": "postCreateCommand",
@@ -59,7 +56,6 @@
         "dbaeumer.vscode-eslint",
         "esbenp.prettier-vscode",
         "vitest.explorer",
-        "ms-azuretools.vscode-docker",
         "redhat.vscode-yaml",
         "yzhang.markdown-all-in-one",
         "ms-python.python",