feat: add prerelease RPM builds from upstream main branch

Poll upstream main branch HEAD alongside release tags. When a new commit
is detected, build and publish prerelease RPMs to a separate unstable
repo at rpm.lair.cafe/fedora/$releasever/$basearch/unstable/.

RPM versioning uses the Fedora snapshot convention (e.g.
0.8.1-0.1.20260511git1a2b3c4.fc43) so stable releases automatically
supersede any installed prerelease.

- RPM spec: conditional Release field via mistralrs_prerelease define
- poll-upstream.yml: new check-prerelease job fetches main HEAD + Cargo.toml version
- build-prerelease.yml: new workflow for commit-based builds without --locked
- UI: fetch both stable/unstable manifests, show channel badges, add
  unstable repo setup instructions to home page

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

ui/src/hooks/usePackages.ts

@@ -1,23 +1,47 @@
 import { useEffect, useState } from "react";
-import type { PackagesManifest } from "../types/packages.ts";
+import type { Channel, PackagesManifest, PackageVersion } from "../types/packages.ts";
 
-const MANIFEST_URL = "/fedora/43/x86_64/packages.json";
+const STABLE_URL = "/fedora/43/x86_64/packages.json";
+const UNSTABLE_URL = "/fedora/43/x86_64/unstable/packages.json";
+
+function tagPackages(
+  manifest: PackagesManifest,
+  channel: Channel,
+): PackageVersion[] {
+  return manifest.packages.map((p) => ({
+    ...p,
+    channel,
+    baseUrl: manifest.baseUrl,
+  }));
+}
 
 export function usePackages() {
-  const [manifest, setManifest] = useState<PackagesManifest | null>(null);
+  const [packages, setPackages] = useState<PackageVersion[]>([]);
   const [loading, setLoading] = useState(true);
   const [error, setError] = useState<string | null>(null);
 
   useEffect(() => {
     let cancelled = false;
 
-    fetch(MANIFEST_URL)
-      .then((res) => {
-        if (!res.ok) throw new Error(`HTTP ${res.status}`);
-        return res.json() as Promise<PackagesManifest>;
-      })
-      .then((data) => {
-        if (!cancelled) setManifest(data);
+    const fetchManifest = async (
+      url: string,
+      channel: Channel,
+    ): Promise<PackageVersion[]> => {
+      const res = await fetch(url);
+      if (!res.ok) {
+        if (res.status === 404) return [];
+        throw new Error(`HTTP ${res.status} fetching ${channel} manifest`);
+      }
+      const data = (await res.json()) as PackagesManifest;
+      return tagPackages(data, channel);
+    };
+
+    Promise.all([
+      fetchManifest(STABLE_URL, "stable"),
+      fetchManifest(UNSTABLE_URL, "unstable"),
+    ])
+      .then(([stable, unstable]) => {
+        if (!cancelled) setPackages([...stable, ...unstable]);
       })
       .catch((err: unknown) => {
         if (!cancelled)
@@ -32,5 +56,5 @@ export function usePackages() {
     };
   }, []);
 
-  return { manifest, loading, error };
+  return { packages, loading, error };
 }

ui/src/pages/Home.tsx

@@ -10,6 +10,13 @@ enabled=1
 gpgcheck=1
 gpgkey=${GPG_KEY_URL}`;
 
+const UNSTABLE_REPO_FILE = `[lair-cafe-unstable]
+name=lair.cafe RPM Repository (unstable)
+baseurl=https://rpm.lair.cafe/fedora/$releasever/$basearch/unstable/
+enabled=0
+gpgcheck=1
+gpgkey=${GPG_KEY_URL}`;
+
 export function Home() {
   return (
     <>
@@ -43,6 +50,50 @@ export function Home() {
             </Card.Body>
           </Card>
         </Col>
+
+        <Col lg={12}>
+          <Card>
+            <Card.Body>
+              <Card.Title>Unstable (prerelease) packages</Card.Title>
+              <p>
+                Unstable packages are built automatically from the latest
+                upstream <code>main</code> branch commit. They use the
+                next release version from <code>Cargo.toml</code> with a
+                prerelease suffix (e.g.{" "}
+                <code>0.8.1-0.1.20260511git1a2b3c4</code>). When the
+                upstream version is officially released, the stable package
+                will automatically supersede any installed prerelease.
+              </p>
+
+              <h6 className="mt-4">Add the unstable repository</h6>
+              <p className="text-body-secondary">
+                The unstable repo is disabled by default. Add it alongside the
+                stable repo:
+              </p>
+              <CodeBlock language="bash">
+                {`sudo dnf config-manager addrepo --from-repofile=/dev/stdin <<'EOF'\n${UNSTABLE_REPO_FILE}\nEOF`}
+              </CodeBlock>
+
+              <h6 className="mt-4">
+                Install or update from unstable
+              </h6>
+              <CodeBlock language="bash">
+                {`sudo dnf --enablerepo=lair-cafe-unstable install mistralrs-cuda13`}
+              </CodeBlock>
+
+              <h6 className="mt-4">
+                Pin to stable
+              </h6>
+              <p className="text-body-secondary">
+                If you have the unstable repo enabled and want to stay on
+                stable releases, exclude prerelease versions:
+              </p>
+              <CodeBlock language="bash">
+                {`sudo dnf --disablerepo=lair-cafe-unstable update mistralrs-cuda13`}
+              </CodeBlock>
+            </Card.Body>
+          </Card>
+        </Col>
       </Row>
     </>
   );

ui/src/pages/PackageDetail.tsx

@@ -11,13 +11,13 @@ function formatBytes(bytes: number): string {
 
 export function PackageDetail() {
   const { name } = useParams<{ name: string }>();
-  const { manifest, loading, error } = usePackages();
+  const { packages, loading, error } = usePackages();
 
   if (loading) return <Spinner animation="border" />;
   if (error) return <Alert variant="danger">Failed to load packages: {error}</Alert>;
-  if (!manifest) return <Alert variant="info">No package data available.</Alert>;
+  if (packages.length === 0) return <Alert variant="info">No package data available.</Alert>;
 
-  const versions = manifest.packages
+  const versions = packages
     .filter((p) => p.name === name)
     .sort((a, b) => b.buildTime - a.buildTime);
 
@@ -25,6 +25,7 @@ export function PackageDetail() {
     return <Alert variant="warning">Package not found: {name}</Alert>;
 
   const latest = versions[0];
+  const hasUnstable = versions.some((v) => v.channel === "unstable");
 
   return (
     <>
@@ -33,6 +34,14 @@ export function PackageDetail() {
 
       <CodeBlock language="bash">{`sudo dnf install ${name}`}</CodeBlock>
 
+      {hasUnstable && (
+        <div className="mt-3">
+          <CodeBlock language="bash">
+            {`# install latest unstable version\nsudo dnf --enablerepo=lair-cafe-unstable install ${name}`}
+          </CodeBlock>
+        </div>
+      )}
+
       <h2 className="mt-4 mb-3">
         Versions <Badge bg="secondary">{versions.length}</Badge>
       </h2>
@@ -41,6 +50,7 @@ export function PackageDetail() {
         <thead>
           <tr>
             <th>Version</th>
+            <th>Channel</th>
             <th>Size</th>
             <th>Built</th>
             <th>Download</th>
@@ -48,14 +58,19 @@ export function PackageDetail() {
         </thead>
         <tbody>
           {versions.map((pkg) => (
-            <tr key={`${pkg.version}-${pkg.release}`}>
+            <tr key={`${pkg.version}-${pkg.release}-${pkg.channel}`}>
               <td>
                 {pkg.version}-{pkg.release}
               </td>
+              <td>
+                <Badge bg={pkg.channel === "stable" ? "success" : "warning"}>
+                  {pkg.channel}
+                </Badge>
+              </td>
               <td>{formatBytes(pkg.size)}</td>
               <td>{new Date(pkg.buildTime * 1000).toLocaleDateString()}</td>
               <td>
-                <a href={`${manifest.baseUrl}/${pkg.rpmFilename}`}>
+                <a href={`${pkg.baseUrl}/${pkg.rpmFilename}`}>
                   {pkg.rpmFilename}
                 </a>
               </td>

ui/src/pages/PackageList.tsx

@@ -1,21 +1,29 @@
-import { Alert, Spinner, Table } from "react-bootstrap";
+import { Alert, Badge, Spinner, Table } from "react-bootstrap";
 import { Link } from "react-router";
 import { usePackages } from "../hooks/usePackages.ts";
 
 export function PackageList() {
-  const { manifest, loading, error } = usePackages();
+  const { packages, loading, error } = usePackages();
 
   if (loading) return <Spinner animation="border" />;
   if (error) return <Alert variant="danger">Failed to load packages: {error}</Alert>;
-  if (!manifest || manifest.packages.length === 0)
+  if (packages.length === 0)
     return <Alert variant="info">No packages published yet.</Alert>;
 
-  const byName = Map.groupBy(manifest.packages, (p) => p.name);
+  const byName = Map.groupBy(packages, (p) => p.name);
   const summaries = [...byName.entries()].map(([name, versions]) => {
+    const stable = versions.filter((v) => v.channel === "stable");
+    const unstable = versions.filter((v) => v.channel === "unstable");
     const latest = versions.reduce((a, b) =>
       a.buildTime >= b.buildTime ? a : b,
     );
-    return { name, latest, versionCount: versions.length };
+    return {
+      name,
+      latest,
+      stableCount: stable.length,
+      unstableCount: unstable.length,
+      versionCount: versions.length,
+    };
   });
   summaries.sort((a, b) => a.name.localeCompare(b.name));
 
@@ -33,15 +41,25 @@ export function PackageList() {
           </tr>
         </thead>
         <tbody>
-          {summaries.map(({ name, latest, versionCount }) => (
+          {summaries.map(({ name, latest, stableCount, unstableCount }) => (
             <tr key={name}>
               <td>
                 <Link to={`/packages/${name}`}>{name}</Link>
               </td>
               <td>
-                {latest.version}-{latest.release}
+                {latest.version}-{latest.release}{" "}
+                <Badge bg={latest.channel === "stable" ? "success" : "warning"} className="ms-1">
+                  {latest.channel}
+                </Badge>
+              </td>
+              <td>
+                {stableCount > 0 && (
+                  <Badge bg="success" className="me-1">{stableCount} stable</Badge>
+                )}
+                {unstableCount > 0 && (
+                  <Badge bg="warning">{unstableCount} unstable</Badge>
+                )}
               </td>
-              <td>{versionCount}</td>
               <td>{latest.summary}</td>
               <td>{new Date(latest.buildTime * 1000).toLocaleDateString()}</td>
             </tr>

ui/src/types/packages.ts

@@ -4,6 +4,8 @@ export interface ChangelogEntry {
   text: string;
 }
 
+export type Channel = "stable" | "unstable";
+
 export interface PackageVersion {
   name: string;
   version: string;
@@ -14,6 +16,8 @@ export interface PackageVersion {
   buildTime: number;
   rpmFilename: string;
   changelog: ChangelogEntry[];
+  channel: Channel;
+  baseUrl: string;
 }
 
 export interface PackagesManifest {