feat(backend): enforce user-owned sessions

backend/src/tht/tht-runner.ts

@@ -1,6 +1,7 @@
 import { spawn } from "node:child_process";
 import { existsSync } from "node:fs";
 import { join } from "node:path";
+import { principalEnvironment, type PrincipalContext } from "../auth/principal.js";
 
 export interface ThtConfig {
   thtBin: string;
@@ -37,7 +38,10 @@ export interface OllamaEnsureResult {
 }
 
 export class ThtRunner {
-  constructor(private cfg: ThtConfig) {}
+  constructor(private cfg: ThtConfig, private principal?: PrincipalContext) {}
+
+  /** Bind one trusted request principal to every child spawned by this runner. */
+  withPrincipal(principal: PrincipalContext): ThtRunner { return new ThtRunner(this.cfg, principal); }
 
   /**
    * Resolve the `-c <config>` args. If `workspace` is given AND a matching
@@ -65,15 +69,23 @@ export class ThtRunner {
       const env: NodeJS.ProcessEnv = { ...process.env };
       delete env.THT_DATA_ROOT;
       if (this.cfg.dataRoot !== undefined) env.THT_DATA_ROOT = this.cfg.dataRoot;
+      if (this.principal) Object.assign(env, principalEnvironment(this.principal));
       const ch = spawn(this.cfg.thtBin, this.buildArgv(args, workspace), {
         cwd: this.cfg.harnessDir,
         env,
       });
       let stdout = "";
       let stderr = "";
+      let settled = false;
+      const finish = (result: { code: number; stdout: string; stderr: string }) => {
+        if (settled) return;
+        settled = true;
+        resolve(result);
+      };
       ch.stdout.on("data", (d: Buffer) => (stdout += d));
       ch.stderr.on("data", (d: Buffer) => (stderr += d));
-      ch.on("close", (code) => resolve({ code: code ?? 0, stdout, stderr }));
+      ch.on("error", (error) => finish({ code: 1, stdout, stderr: stderr || error.message }));
+      ch.on("close", (code) => finish({ code: code ?? 0, stdout, stderr }));
     });
   }
 
@@ -124,7 +136,7 @@ export class ThtRunner {
     return this.json<unknown>(["session", "show", id, "--json"], workspace);
   }
 
-  sqlPreview(id: string, p: { limit?: number; offset?: number }) {
+  sqlPreview(id: string, p: { limit?: number; offset?: number }, workspace?: string) {
     // No positional FILE: the harness resolves sql_final.sql from the session
     // via _session_sql_file(cfg, session_id), which respects the workspace path.
     const a = ["sql", "preview", "--session", id, "--json"];
@@ -135,11 +147,11 @@ export class ThtRunner {
       rows: unknown[][];
       execution_ms: number;
       truncated: boolean;
-    }>(a);
+    }>(a, workspace);
   }
 
-  async sqlExport(id: string) {
-    const { code, stdout, stderr } = await this.run(["sql", "export", "--session", id]);
+  async sqlExport(id: string, workspace?: string) {
+    const { code, stdout, stderr } = await this.run(["sql", "export", "--session", id], workspace);
     if (code !== 0) throw new Error(`tht sql export exit ${code}: ${stderr.trim()}`);
     return { path: stdout.trim() };
   }
@@ -157,6 +169,11 @@ export class ThtRunner {
   }
   documents(id: string) { return this.json<SessionDocument[]>(["session", "documents", id, "--json"]); }
 
+  preferencesGet(workspace?: string) { return this.json<Record<string, unknown>>(["session", "preferences", "get", "--json"], workspace); }
+  async preferencesSet(preferences: Record<string, unknown>, workspace?: string): Promise<void> {
+    await this.ok(["session", "preferences", "set", "--json", JSON.stringify(preferences)], workspace);
+  }
+
   async ollamaEnsure(workspace: string, timeoutSec: number): Promise<OllamaEnsureResult> {
     const { code, stdout, stderr } = await this.run(
       ["ollama", "ensure", "--json", "--timeout", String(timeoutSec)],