v0.23.0:0 - local / fine-tuned model support

Add models that live as a directory on a Spark (e.g. LoRA-merged fine-tunes),
not just Hugging Face repos.

- ModelDef gains local_path; a model must set exactly one of repo / local_path.
  The validator also enforces the local-path whitelist and that any
  --chat-template lives inside local_path (only that dir is mounted).
- build_launch_command bind-mounts the dir into the vLLM container at the SAME
  host==container path via the launch script's VLLM_SPARK_EXTRA_DOCKER_ARGS hook,
  then `vllm serve <dir>`. No launch-cluster.sh change (verified the upstream
  expands that var unquoted; contract noted in runbook.md).
- shellsafe.validate_local_path: absolute path, charset whitelist, no '.'/'..'.
- POST /api/models validates the full entry via ModelDef before persisting, so a
  bad entry can't be written and then break catalog load; _merge_overrides skips
  an invalid override entry instead of failing the whole catalog.
- disk.py size-probes a local path with du; disk-delete refused for local models.
- UI: "+ Add local model" dialog, `local` badge, path shown instead of an HF
  link, delete button hidden for local models.
- Tests: local launch + injection round-trip, chat-template location, traversal,
  exactly-one-source, _merge_overrides skip-invalid (94 pass). Reviewer-agent
  pass; findings addressed.

image/app/disk.py

@@ -15,6 +15,7 @@ from dataclasses import dataclass
 from typing import Optional
 
 from .config import Settings
+from .shellsafe import quote_arg
 from .ssh import ssh_run
 
 
@@ -76,16 +77,52 @@ async def probe_host(host: str, user: str, repo: str, settings: Settings) -> Hos
     return HostDiskResult(host=host, on_disk=True, size_bytes=size)
 
 
-async def probe_disk(repo: str, mode: str, settings: Settings) -> DiskStatus:
-    """Probe one model across the relevant Sparks based on its mode (solo|cluster)."""
+async def probe_local_host(host: str, user: str, path: str, settings: Settings) -> HostDiskResult:
+    """Return whether a local model directory exists on this host and its size.
+
+    For locally fine-tuned models (a Spark directory, not an HF cache entry). The
+    path is whitelisted at the API boundary (shellsafe.validate_local_path); we
+    shlex-quote it here in depth.
+    """
+    if not host or not user:
+        return HostDiskResult(host=host or "?", on_disk=False, error="host not configured")
+    qp = quote_arg(path)
+    cmd = f"if [ -d {qp} ]; then du -sb {qp} 2>/dev/null | cut -f1; else echo MISSING; fi"
+    rc, out, err = await ssh_run(host, user, cmd, settings, timeout=20.0)
+    if rc != 0:
+        return HostDiskResult(host=host, on_disk=False, error=(err or out).strip() or f"rc={rc}")
+    raw = out.strip()
+    if raw == "MISSING" or raw == "":
+        return HostDiskResult(host=host, on_disk=False)
+    try:
+        size = int(raw.splitlines()[-1])
+    except ValueError:
+        return HostDiskResult(host=host, on_disk=False, error=f"unparsable du output: {raw!r}")
+    return HostDiskResult(host=host, on_disk=True, size_bytes=size)
+
+
+async def probe_disk(
+    repo: str, mode: str, settings: Settings, *, local_path: str | None = None
+) -> DiskStatus:
+    """Probe one model across the relevant Sparks based on its mode (solo|cluster).
+
+    A local model (local_path set) is probed by directory; otherwise by HF cache.
+    """
     hosts: list[tuple[str, str]] = [(settings.spark1_host, settings.spark1_user)]
     if mode == "cluster" and settings.spark2_host:
         hosts.append((settings.spark2_host, settings.spark2_user))
 
-    results = await asyncio.gather(*(probe_host(h, u, repo, settings) for h, u in hosts))
+    if local_path:
+        results = await asyncio.gather(
+            *(probe_local_host(h, u, local_path, settings) for h, u in hosts)
+        )
+        key = local_path
+    else:
+        results = await asyncio.gather(*(probe_host(h, u, repo, settings) for h, u in hosts))
+        key = repo
     on_disk = any(r.on_disk for r in results)
     total = sum(r.size_bytes for r in results)
-    return DiskStatus(repo=repo, on_disk=on_disk, total_bytes=total, per_host=list(results))
+    return DiskStatus(repo=key, on_disk=on_disk, total_bytes=total, per_host=list(results))
 
 
 async def delete_host(host: str, user: str, repo: str, settings: Settings) -> HostDiskResult: