move pi-mono into companion-cloud as apps/companion-os

- Copy all pi-mono source into apps/companion-os/
- Update Dockerfile to COPY pre-built binary instead of downloading from GitHub Releases
- Update deploy-staging.yml to build pi from source (bun compile) before Docker build
- Add apps/companion-os/** to path triggers
- No more cross-repo dispatch needed

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

packages/coding-agent/src/core/footer-data-provider.ts

@@ -0,0 +1,149 @@
+import { existsSync, type FSWatcher, readFileSync, statSync, watch } from "fs";
+import { dirname, join, resolve } from "path";
+
+/**
+ * Find the git HEAD path by walking up from cwd.
+ * Handles both regular git repos (.git is a directory) and worktrees (.git is a file).
+ */
+function findGitHeadPath(): string | null {
+  let dir = process.cwd();
+  while (true) {
+    const gitPath = join(dir, ".git");
+    if (existsSync(gitPath)) {
+      try {
+        const stat = statSync(gitPath);
+        if (stat.isFile()) {
+          const content = readFileSync(gitPath, "utf8").trim();
+          if (content.startsWith("gitdir: ")) {
+            const gitDir = content.slice(8);
+            const headPath = resolve(dir, gitDir, "HEAD");
+            if (existsSync(headPath)) return headPath;
+          }
+        } else if (stat.isDirectory()) {
+          const headPath = join(gitPath, "HEAD");
+          if (existsSync(headPath)) return headPath;
+        }
+      } catch {
+        return null;
+      }
+    }
+    const parent = dirname(dir);
+    if (parent === dir) return null;
+    dir = parent;
+  }
+}
+
+/**
+ * Provides git branch and extension statuses - data not otherwise accessible to extensions.
+ * Token stats, model info available via ctx.sessionManager and ctx.model.
+ */
+export class FooterDataProvider {
+  private extensionStatuses = new Map<string, string>();
+  private cachedBranch: string | null | undefined = undefined;
+  private gitWatcher: FSWatcher | null = null;
+  private branchChangeCallbacks = new Set<() => void>();
+  private availableProviderCount = 0;
+
+  constructor() {
+    this.setupGitWatcher();
+  }
+
+  /** Current git branch, null if not in repo, "detached" if detached HEAD */
+  getGitBranch(): string | null {
+    if (this.cachedBranch !== undefined) return this.cachedBranch;
+
+    try {
+      const gitHeadPath = findGitHeadPath();
+      if (!gitHeadPath) {
+        this.cachedBranch = null;
+        return null;
+      }
+      const content = readFileSync(gitHeadPath, "utf8").trim();
+      this.cachedBranch = content.startsWith("ref: refs/heads/")
+        ? content.slice(16)
+        : "detached";
+    } catch {
+      this.cachedBranch = null;
+    }
+    return this.cachedBranch;
+  }
+
+  /** Extension status texts set via ctx.ui.setStatus() */
+  getExtensionStatuses(): ReadonlyMap<string, string> {
+    return this.extensionStatuses;
+  }
+
+  /** Subscribe to git branch changes. Returns unsubscribe function. */
+  onBranchChange(callback: () => void): () => void {
+    this.branchChangeCallbacks.add(callback);
+    return () => this.branchChangeCallbacks.delete(callback);
+  }
+
+  /** Internal: set extension status */
+  setExtensionStatus(key: string, text: string | undefined): void {
+    if (text === undefined) {
+      this.extensionStatuses.delete(key);
+    } else {
+      this.extensionStatuses.set(key, text);
+    }
+  }
+
+  /** Internal: clear extension statuses */
+  clearExtensionStatuses(): void {
+    this.extensionStatuses.clear();
+  }
+
+  /** Number of unique providers with available models (for footer display) */
+  getAvailableProviderCount(): number {
+    return this.availableProviderCount;
+  }
+
+  /** Internal: update available provider count */
+  setAvailableProviderCount(count: number): void {
+    this.availableProviderCount = count;
+  }
+
+  /** Internal: cleanup */
+  dispose(): void {
+    if (this.gitWatcher) {
+      this.gitWatcher.close();
+      this.gitWatcher = null;
+    }
+    this.branchChangeCallbacks.clear();
+  }
+
+  private setupGitWatcher(): void {
+    if (this.gitWatcher) {
+      this.gitWatcher.close();
+      this.gitWatcher = null;
+    }
+
+    const gitHeadPath = findGitHeadPath();
+    if (!gitHeadPath) return;
+
+    // Watch the directory containing HEAD, not HEAD itself.
+    // Git uses atomic writes (write temp, rename over HEAD), which changes the inode.
+    // fs.watch on a file stops working after the inode changes.
+    const gitDir = dirname(gitHeadPath);
+
+    try {
+      this.gitWatcher = watch(gitDir, (_eventType, filename) => {
+        if (filename === "HEAD") {
+          this.cachedBranch = undefined;
+          for (const cb of this.branchChangeCallbacks) cb();
+        }
+      });
+    } catch {
+      // Silently fail if we can't watch
+    }
+  }
+}
+
+/** Read-only view for extensions - excludes setExtensionStatus, setAvailableProviderCount and dispose */
+export type ReadonlyFooterDataProvider = Pick<
+  FooterDataProvider,
+  | "getGitBranch"
+  | "getExtensionStatuses"
+  | "getAvailableProviderCount"
+  | "onBranchChange"
+>;