merge: absorb main into next — 23-commit divergence (08-05..13 base=main window)

17 content commits + 3 merge bubbles were genuinely missing from next (~8,000 lines:
goal controller #1152, framework enforcement #1174/#1195, pr-edit wrapper #1173/#1200,
pipefail series #1100/#1105/#1106/#1107, git-tools fixes #1073/#1085/#1086/#1089,
#991, #1007, enrollment tolerance #1094). 3 commits were already in next by content
(#1060 identical, #1066/#1062 evolved twins — conflicts resolved to next's side).

Per-commit classification and evidence: mosaic-brain fleet/lanes/stack-remediation/main-next-divergence.md.
Conflict resolutions (6 files) itemized in the PR body.

packages/mosaic/src/commands/launch.ts

@@ -921,9 +921,15 @@ export function buildPiSkillArgs(
   return ['--no-skills', ...forcedSkillArgs];
 }
 
-function discoverPiExtension(): string[] {
-  const ext = join(MOSAIC_HOME, 'runtime', 'pi', 'mosaic-extension.ts');
-  return existsSync(ext) ? ['--extension', ext] : [];
+const PI_EXTENSION_FILES = ['mosaic-extension.ts', 'goal-extension.ts'] as const;
+
+export function discoverPiExtensionArgs(mosaicHome: string = MOSAIC_HOME): string[] {
+  const args: string[] = [];
+  for (const fileName of PI_EXTENSION_FILES) {
+    const extensionPath = join(mosaicHome, 'runtime', 'pi', fileName);
+    if (existsSync(extensionPath)) args.push('--extension', extensionPath);
+  }
+  return args;
 }
 
 // ─── Launch functions ────────────────────────────────────────────────────────
@@ -1002,7 +1008,7 @@ function launchRuntime(runtime: RuntimeName, args: string[], yolo: boolean): nev
       const prompt = buildRuntimePrompt('pi');
       const cliArgs = ['--append-system-prompt', prompt];
       cliArgs.push(...buildPiSkillArgs(args));
-      cliArgs.push(...discoverPiExtension());
+      cliArgs.push(...discoverPiExtensionArgs());
       if (hasMissionNoArgs) {
         cliArgs.push(missionPrompt);
       } else {