Working chat: auth, connections, streaming, folders

LLeMbas now runs end to end. Register, add an OpenAI-compatible
connection, and hold a real streaming conversation organised into
folders. Verified against the local llama-swap instance.

Streaming is the one genuinely tricky part. Sending a message returns
two HTML fragments -- the user bubble and an empty assistant bubble
carrying an sse-connect -- and that attribute is the ONLY thing that
starts a generation. Rendering an incomplete assistant message as a
streaming shell falls out of the same template, which means loading a
page whose last reply never finished simply picks it up again.

Details worth knowing about, each commented where it matters:

- SSE payloads are split across several data: lines. A raw newline in
  one data: line truncates the event, which shows up the first time a
  model emits a code block.
- Markdown is rendered server-side by the same helper for both the page
  and the final streamed frame, so the two cannot disagree. The fence
  renderer is replaced outright rather than using markdown-it's
  highlight option, which re-wraps output in a second <pre>.
- escape_text is html.escape, not nh3.clean_text: it escapes character
  by character, so escaping stream chunks separately equals escaping
  the whole string.
- The stream opens its own session via session_scope(); it outlives the
  request handler and the dependency-scoped session may be closed.
- Deleting a folder keeps the chats inside it (FK is SET NULL). Losing
  a conversation to a mis-clicked folder delete is unforgivable.
- Login failures use one message for "no such account" and "wrong
  password" so the form cannot enumerate registered addresses.

Also adds deploy/ for the gamebox install at https://chat.lan: system
unit, nginx vhost with buffering off (buffering on turns streaming into
one lump at the end), and install/update scripts following the same
service-user and /srv bind-mount conventions as llama-swap and comfyui.

70 tests, ruff clean.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

scripts/build_artwork.py

@@ -35,6 +35,11 @@ except ImportError:  # pragma: no cover - design-time tool
 
 ROOT = Path(__file__).resolve().parent.parent
 ASSETS = ROOT / "assets"
+STATIC_IMG = ROOT / "src" / "lembas" / "web" / "static" / "img"
+
+# assets/ holds the design masters; the application serves its own copies from
+# static/. These are the few the running app actually needs.
+SERVED_BY_APP = ("favicon.svg", "logo-mark.svg", "banner.svg")
 
 FONT_SEMIBOLD = Path("/usr/share/fonts/adobe-source-serif/SourceSerif4Display-Semibold.otf")
 FONT_ITALIC = Path("/usr/share/fonts/adobe-source-serif/SourceSerif4Display-It.otf")
@@ -463,10 +468,18 @@ def main() -> None:
     args = parser.parse_args()
 
     args.out.mkdir(parents=True, exist_ok=True)
+    STATIC_IMG.mkdir(parents=True, exist_ok=True)
+
     for filename in args.only or BUILDERS:
+        content = BUILDERS[filename]()
         path = args.out / filename
-        path.write_text(BUILDERS[filename](), encoding="utf-8")
-        print(f"wrote {path.relative_to(ROOT)} ({path.stat().st_size:,} bytes)")
+        path.write_text(content, encoding="utf-8")
+        print(f"wrote {path.relative_to(ROOT)} ({len(content.encode()):,} bytes)")
+
+        if filename in SERVED_BY_APP:
+            served = STATIC_IMG / filename
+            served.write_text(content, encoding="utf-8")
+            print(f"      -> {served.relative_to(ROOT)}")
 
 
 if __name__ == "__main__":

scripts/fetch_vendor.py

@@ -0,0 +1,119 @@
+#!/usr/bin/env python3
+"""Download the pinned browser libraries into the static vendor directory.
+
+LLeMbas has no Node toolchain and loads nothing from a CDN at runtime -- a
+self-hosted tool should keep working without internet access, and should not
+report every user's page view to a third party. The three libraries it does use
+are fetched once, here, and committed.
+
+Integrity is enforced with vendor.lock.json. A mismatched hash aborts rather
+than overwriting: that is the whole point of pinning.
+
+    python scripts/fetch_vendor.py            # fetch and verify against the lock
+    python scripts/fetch_vendor.py --update   # re-pin after a version bump
+"""
+
+from __future__ import annotations
+
+import argparse
+import hashlib
+import json
+import sys
+import urllib.error
+import urllib.request
+from pathlib import Path
+
+ROOT = Path(__file__).resolve().parent.parent
+VENDOR_DIR = ROOT / "src" / "lembas" / "web" / "static" / "vendor"
+LOCKFILE = Path(__file__).resolve().parent / "vendor.lock.json"
+
+# Pinned deliberately. Bump the version, run with --update, review the diff.
+PACKAGES = {
+    "htmx.min.js": {
+        "version": "2.0.10",
+        "url": "https://unpkg.com/htmx.org@2.0.10/dist/htmx.min.js",
+        "why": "Server-rendered interactivity: every swap in the app.",
+    },
+    "htmx-ext-sse.js": {
+        "version": "2.2.4",
+        "url": "https://unpkg.com/htmx-ext-sse@2.2.4/sse.js",
+        "why": "Server-sent events, which is how streamed replies reach the page.",
+    },
+    "alpine.min.js": {
+        "version": "3.15.12",
+        "url": "https://unpkg.com/alpinejs@3.15.12/dist/cdn.min.js",
+        "why": "Small client-only state: menus, theme toggle, composer autosize.",
+    },
+}
+
+
+def sha256(data: bytes) -> str:
+    return hashlib.sha256(data).hexdigest()
+
+
+def fetch(url: str) -> bytes:
+    request = urllib.request.Request(url, headers={"User-Agent": "lembas-vendor-fetch"})
+    with urllib.request.urlopen(request, timeout=60) as response:  # noqa: S310
+        return response.read()
+
+
+def main() -> int:
+    parser = argparse.ArgumentParser(description=__doc__)
+    parser.add_argument(
+        "--update",
+        action="store_true",
+        help="rewrite vendor.lock.json with the hashes just downloaded",
+    )
+    args = parser.parse_args()
+
+    lock = json.loads(LOCKFILE.read_text()) if LOCKFILE.exists() else {}
+    VENDOR_DIR.mkdir(parents=True, exist_ok=True)
+
+    new_lock: dict[str, dict[str, str]] = {}
+    failed = False
+
+    for filename, spec in PACKAGES.items():
+        try:
+            payload = fetch(spec["url"])
+        except (urllib.error.URLError, TimeoutError) as exc:
+            print(f"  FAIL {filename}: {exc}", file=sys.stderr)
+            failed = True
+            continue
+
+        digest = sha256(payload)
+        expected = lock.get(filename, {}).get("sha256")
+
+        if expected and digest != expected and not args.update:
+            print(
+                f"  FAIL {filename}: hash mismatch\n"
+                f"       expected {expected}\n"
+                f"       received {digest}\n"
+                f"       Refusing to overwrite. If the version was bumped "
+                f"deliberately, re-run with --update.",
+                file=sys.stderr,
+            )
+            failed = True
+            continue
+
+        (VENDOR_DIR / filename).write_bytes(payload)
+        new_lock[filename] = {
+            "version": spec["version"],
+            "url": spec["url"],
+            "sha256": digest,
+        }
+        status = "ok" if expected == digest else ("pinned" if args.update else "new")
+        print(f"  {status:>6}  {filename}  {len(payload):>8,} bytes  v{spec['version']}")
+
+    if failed:
+        print("\nOne or more downloads failed. Vendored files were not fully written.")
+        return 1
+
+    if args.update or not LOCKFILE.exists():
+        LOCKFILE.write_text(json.dumps(new_lock, indent=2, sort_keys=True) + "\n")
+        print(f"\nwrote {LOCKFILE.relative_to(ROOT)}")
+
+    return 0
+
+
+if __name__ == "__main__":
+    sys.exit(main())

scripts/vendor.lock.json

@@ -0,0 +1,17 @@
+{
+  "alpine.min.js": {
+    "sha256": "57b37d7cae9a27d965fdae4adcc844245dfdc407e655aee85dcfff3a08036a3f",
+    "url": "https://unpkg.com/alpinejs@3.15.12/dist/cdn.min.js",
+    "version": "3.15.12"
+  },
+  "htmx-ext-sse.js": {
+    "sha256": "3b5992a541619babefc4c169505af474df5c3039da51e59b96ccf9241ecd61d2",
+    "url": "https://unpkg.com/htmx-ext-sse@2.2.4/sse.js",
+    "version": "2.2.4"
+  },
+  "htmx.min.js": {
+    "sha256": "71ea67185bfa8c98c39d31717c6fce5d852370fcdfd129db4543774d3145c0de",
+    "url": "https://unpkg.com/htmx.org@2.0.10/dist/htmx.min.js",
+    "version": "2.0.10"
+  }
+}