fix(update): make Camofox lazy-installed instead of eager (#27055)

The `@askjo/camofox-browser` npm package was a top-level entry in
the root `package.json` `dependencies` block, so `hermes update`
ran its postinstall on every user, every update. That postinstall
calls `npx camoufox-js fetch`, which silently downloads a ~300MB
Firefox-fork browser binary from GitHub Releases — multi-minute on
fast connections, and a hard block for users on slow / restricted
networks (notably users in China running through a VPN).

Camofox is an explicit opt-in browser backend. The runtime check
in `tools/browser_tool.py` only routes through Camofox when the
user has set `CAMOFOX_URL` (selected via `hermes tools` →
Browser Automation → Camofox). Users who never opted in never
touched the package at runtime, yet every `hermes update` paid
for the binary fetch anyway.

This change:

* Removes `@askjo/camofox-browser` from root `package.json`
  dependencies (and the regenerated `package-lock.json` drops
  Camofox's entire transitive tree, ~2.6k lines).
* Updates the Camofox `post_setup` handler in
  `hermes_cli/tools_config.py` to install
  `@askjo/camofox-browser@^1.5.2` explicitly when the user
  selects Camofox, and streams npm output (no `--silent`, no
  `capture_output`) so the ~300MB download is visible rather
  than appearing frozen.
* Adds `tests/test_package_json_lazy_deps.py` as a regression
  guard so future PRs can't silently re-add Camofox (or any
  binary-postinstall package) to eager root dependencies.

`agent-browser` stays eager — it is the default Chromium-driving
backend used by every session that does not have a cloud browser
provider configured, and its postinstall is small.

Validation:

| | Before | After |
|---|---|---|
| `hermes update` time on slow network | multi-minute hang at `→ Updating Node.js dependencies...` | seconds (no binary fetch) |
| Camofox opt-in install visibility | silent, looked frozen | streamed npm output |
| Regression guard against re-adding | none | `test_package_json_lazy_deps.py` |

Tests:
- `tests/test_package_json_lazy_deps.py`: 3/3 pass
- `tests/tools/test_browser_camofox*`: 92/92 pass
- `tests/hermes_cli/test_tools_config.py`: 66/66 pass
- `tests/hermes_cli/test_cmd_update.py` + adjacent: green

Reported by lulu (Discord, May 2026) — `hermes update` hangs at
`→ Updating Node.js dependencies...` in China.
Related: #18840, #18869.

hermes_cli/tools_config.py

@@ -810,21 +810,35 @@ def _run_post_setup(post_setup_key: str):
         camofox_dir = PROJECT_ROOT / "node_modules" / "@askjo" / "camofox-browser"
         _npm_bin = shutil.which("npm")
         if not camofox_dir.exists() and _npm_bin:
-            _print_info("    Installing Camofox browser server...")
+            _print_info("    Installing Camofox browser package...")
+            _print_info("    First run downloads the Camoufox engine (~300MB) — this can take several minutes.")
             import subprocess
-            # Absolute npm path so .cmd shim executes on Windows.
-            result = subprocess.run(
-                [_npm_bin, "install", "--silent"],
-                capture_output=True, text=True, cwd=str(PROJECT_ROOT)
-            )
-            if result.returncode == 0:
-                _print_success("    Camofox installed")
-            else:
-                _print_warning("    npm install failed - run manually: npm install")
+            # Install @askjo/camofox-browser on-demand. It is NOT in
+            # package.json so that `hermes update` does not silently pull
+            # the ~300MB Camoufox Firefox-fork binary for every user.
+            # Stream output (no capture, no --silent) so the long-running
+            # postinstall download is visible instead of looking frozen.
+            try:
+                result = subprocess.run(
+                    [_npm_bin, "install", "@askjo/camofox-browser@^1.5.2",
+                     "--no-fund", "--no-audit", "--progress=false"],
+                    cwd=str(PROJECT_ROOT),
+                )
+                if result.returncode == 0:
+                    _print_success("    Camofox installed")
+                else:
+                    _print_warning(
+                        "    npm install failed — run manually: "
+                        "npm install @askjo/camofox-browser"
+                    )
+            except Exception as exc:
+                _print_warning(f"    Camofox install failed: {exc}")
+                _print_info(
+                    "    Run manually: npm install @askjo/camofox-browser"
+                )
         if camofox_dir.exists():
             _print_info("    Start the Camofox server:")
             _print_info("      npx @askjo/camofox-browser")
-            _print_info("    First run downloads the Camoufox engine (~300MB)")
             _print_info("    Or use Docker: docker run -p 9377:9377 -e CAMOFOX_PORT=9377 jo-inc/camofox-browser")
         elif not shutil.which("npm"):
             _print_warning("    Node.js not found. Install Camofox via Docker:")