refactor(f8): controllers depend on SidecarRouter + isAuthorable (key via keyOf)

Spec §6.4: constructor store CoauthorStore→SidecarRouter, rootDir→string|undefined;
isInRoot/isTracked gate → isAuthorable(scheme); per-doc key via store.keyOf(docIdentity).
Seam + artifact logic unchanged. currentAuthor omits git email when no root (fail-open).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/threadController.ts

@@ -8,13 +8,13 @@
  * orphaned thread (INV-1).
  */
 import * as vscode from "vscode";
-import { CoauthorStore } from "./store";
+import { SidecarRouter, docIdentity } from "./sidecarRouter";
 import { emptyArtifact, type Artifact, type Provenance } from "./model";
 import { buildFingerprint, resolve, shift, type OffsetRange } from "./anchorer";
 import { gitUserEmail } from "./identity";
 import { addThread, appendMessage, setStatus } from "./threadModel";
 import type { VersionGuard } from "./versionGuard";
-import { isUnderRoot } from "./workspacePath";
+import { isAuthorable } from "./workspacePath";
 
 /** Test-facing snapshot of what is currently rendered for a document. */
 export interface RenderedThread {
@@ -42,14 +42,14 @@ export class ThreadController implements vscode.Disposable {
   private readonly docs = new Map<string, DocState>(); // keyed by docPath
 
   constructor(
-    private readonly store: CoauthorStore,
-    private readonly rootDir: string,
+    private readonly store: SidecarRouter,
+    private readonly rootDir: string | undefined,
     private readonly guard: VersionGuard,
   ) {
     this.controller = vscode.comments.createCommentController("cowriting.threads", "Coauthoring Threads");
     this.controller.commentingRangeProvider = {
       provideCommentingRanges: (document) => {
-        if (!this.isInRoot(document.uri)) return [];
+        if (!isAuthorable(document.uri.scheme)) return [];
         return [new vscode.Range(0, 0, Math.max(0, document.lineCount - 1), 0)];
       },
     };
@@ -69,17 +69,14 @@ export class ThreadController implements vscode.Disposable {
     );
   }
 
-  private isInRoot(uri: vscode.Uri): boolean {
-    return uri.scheme === "file" && isUnderRoot(uri.fsPath, this.rootDir);
-  }
-
-  private docPathOf(uri: vscode.Uri): string {
-    return vscode.workspace.asRelativePath(uri, false);
+  /** The single document key (F8): repo-relative path in-workspace, URI string otherwise. */
+  private keyOf(document: vscode.TextDocument): string {
+    return this.store.keyOf(docIdentity(document));
   }
 
   private currentAuthor(): Provenance {
     const id = vscode.workspace.getConfiguration("git").get<string>("user.name") || process.env.USER || "human";
-    const email = gitUserEmail(this.rootDir);
+    const email = this.rootDir !== undefined ? gitUserEmail(this.rootDir) : undefined;
     return { kind: "human", id, ...(email !== undefined ? { email } : {}) };
   }
 
@@ -93,7 +90,7 @@ export class ThreadController implements vscode.Disposable {
   }
 
   private ensureState(document: vscode.TextDocument): DocState {
-    const docPath = this.docPathOf(document.uri);
+    const docPath = this.keyOf(document);
     let state = this.docs.get(docPath);
     if (!state) {
       state = {
@@ -113,8 +110,8 @@ export class ThreadController implements vscode.Disposable {
 
   async createThreadOnSelection(firstBody = "New thread"): Promise<string | undefined> {
     const editor = vscode.window.activeTextEditor;
-    if (!editor || editor.selection.isEmpty || !this.isInRoot(editor.document.uri)) return undefined;
-    if (this.guard.isReadOnly(this.docPathOf(editor.document.uri))) return undefined;
+    if (!editor || editor.selection.isEmpty || !isAuthorable(editor.document.uri.scheme)) return undefined;
+    if (this.guard.isReadOnly(this.keyOf(editor.document))) return undefined;
     const document = editor.document;
     const state = this.ensureState(document);
     const offsets: OffsetRange = {
@@ -155,7 +152,7 @@ export class ThreadController implements vscode.Disposable {
 
   /** Load + (re)render every thread for a document at its resolved anchor (or orphaned). */
   renderAll(document: vscode.TextDocument): void {
-    const docPath = this.docPathOf(document.uri);
+    const docPath = this.keyOf(document);
     const state = this.ensureState(document);
     // fresh artifact from disk (reload / external change)
     state.artifact = this.store.load(docPath) ?? emptyArtifact(docPath);
@@ -182,14 +179,14 @@ export class ThreadController implements vscode.Disposable {
     const p = uri.fsPath;
     for (const state of this.docs.values()) {
       if (this.store.sidecarPath(state.docPath) === p) {
-        const doc = vscode.workspace.textDocuments.find((d) => this.docPathOf(d.uri) === state.docPath);
+        const doc = vscode.workspace.textDocuments.find((d) => this.keyOf(d) === state.docPath);
         if (doc) this.renderAll(doc);
       }
     }
   }
 
   private onDidChange(e: vscode.TextDocumentChangeEvent): void {
-    const state = this.docs.get(this.docPathOf(e.document.uri));
+    const state = this.docs.get(this.keyOf(e.document));
     if (!state || state.live.size === 0) return;
     for (const change of e.contentChanges) {
       const edit = { start: change.rangeOffset, end: change.rangeOffset + change.rangeLength, newLength: change.text.length };
@@ -205,7 +202,7 @@ export class ThreadController implements vscode.Disposable {
   }
 
   private onDidSave(document: vscode.TextDocument): void {
-    const state = this.docs.get(this.docPathOf(document.uri));
+    const state = this.docs.get(this.keyOf(document));
     if (!state || state.live.size === 0) return;
     if (this.guard.isReadOnly(state.docPath)) return;
     const text = document.getText();