feat(verify-release): wire quality-rails evaluator stage into canonical verification (#1275)

- new canonical-only quality-rails stage (after build) invokes the evaluator
  CLI on the repo root — QC-19 monorepo subject — instead of duplicating
  presence logic; no ci.yml mirror (same shape as the build stage)
- parity spec updated: stage-name list, evaluator-delegation assertions, and
  negative controls for inline duplication / dropped command
- quality-rails README points at the probe inventory (input doc)

packages/mosaic/src/commands/fleet-roster-v2-dispatch.spec.ts

@@ -244,115 +244,12 @@ describe('[email protected]', (): void => {
    * absent env — either of which turns the condition into decoration while the
    * literal-string assertion above still passes.
    */
-  /**
-   * The condition an installed unit actually presents to systemd: the shipped
-   * unit's values with drop-ins applied in lexical order, honouring the list
-   * reset an empty assignment performs.
-   *
-   * Reading the *installed* tree rather than the template is the point. The
-   * template alone cannot show what `install` produced, and #1310 lived in that
-   * gap: the template was correct for the install it was written for, and wrong
-   * for the one the operator had.
-   */
-  async function effectiveConditionPaths(systemdUserDir: string): Promise<string[]> {
-    const dropInDir = join(systemdUserDir, '[email protected]');
-    const dropIns = (
-      await readdir(dropInDir).catch((error: NodeJS.ErrnoException): string[] => {
-        if (error.code === 'ENOENT') return [];
-        throw error;
-      })
-    )
-      .filter((name): boolean => name.endsWith('.conf'))
-      .sort();
-    const sources = [
-      join(systemdUserDir, '[email protected]'),
-      ...dropIns.map((name): string => join(dropInDir, name)),
-    ];
-    const conditions: string[] = [];
-    for (const source of sources) {
-      for (const line of (await readFile(source, 'utf8')).split('\n')) {
-        const match = line.match(/^ConditionPathExists=(.*)$/);
-        if (!match) continue;
-        const value = match[1]!.trim();
-        if (value === '') conditions.length = 0;
-        else conditions.push(value);
-      }
-    }
-    return conditions;
-  }
-
-  /** Makes `~/.mosaic` adoptable — the shape that puts a real box in split mode. */
-  async function adoptableBrainHome(): Promise<string> {
-    const brainHome = join(tempHome!, '.mosaic');
-    await mkdir(join(brainHome, 'fleet', 'agents'), { recursive: true, mode: 0o700 });
-    return brainHome;
-  }
-
   it('guards exactly the file the fleet writes, so the two cannot drift apart', async (): Promise<void> => {
     const mosaicHome = await v2Home();
-    const systemdUserDir = join(tempHome!, '.config', 'systemd', 'user');
-
-    await program().parseAsync(['node', 'mosaic', 'fleet', 'install', '--no-enable']);
-
-    const rendered = (await effectiveConditionPaths(systemdUserDir)).map((value): string =>
-      value.replace('%h', tempHome!).replace('%i', 'coder0'),
-    );
+    const rendered = (await conditionPath()).replace('%h', tempHome!).replace('%i', 'coder0');
 
     // The path an installed fleet actually places for this agent.
-    expect(rendered).toEqual([join(mosaicHome, 'fleet', 'agents', 'coder0.env.generated')]);
-  });
-
-  /**
-   * #1310. The test above passed throughout the bug, because its fixture never
-   * creates `~/.mosaic/fleet/agents` and so can only ever reach legacy mode,
-   * where brain home and config home are the same directory and the drift it
-   * names is unobservable. A guard that cannot reach the state it guards is
-   * decoration; this is the arm that reaches it.
-   *
-   * Measured consequence on a real box (mosaic-sbx-dev 1124, 0.0.50-next.2507):
-   * the config-home condition can never be met, systemd reports every seat
-   * `ConditionResult=no` with `Result=success` and `ExecMainStatus=0`, and
-   * `fleet start` exits 0 having started nothing.
-   */
-  it('follows the brain home when one is active, not the config home', async (): Promise<void> => {
-    const mosaicHome = await v2Home();
-    const brainHome = await adoptableBrainHome();
-    const systemdUserDir = join(tempHome!, '.config', 'systemd', 'user');
-
-    await program().parseAsync(['node', 'mosaic', 'fleet', 'install', '--no-enable']);
-
-    const rendered = (await effectiveConditionPaths(systemdUserDir)).map((value): string =>
-      value.replace('%h', tempHome!).replace('%i', 'coder0'),
-    );
-
-    // Exactly one condition: the drop-in must reset the shipped value, not join
-    // it. Two conditions would both have to pass and the seat would stay skipped.
-    expect(rendered).toEqual([join(brainHome, 'fleet', 'agents', 'coder0.env.generated')]);
-    expect(rendered[0]).not.toContain(mosaicHome);
-  });
-
-  /**
-   * The other direction, which fails the same silent way: a box that had a
-   * brain home and no longer does would keep a condition pointing at a path the
-   * reconciler has stopped writing.
-   */
-  it('drops a stale brain-home override when the brain home goes away', async (): Promise<void> => {
-    const mosaicHome = await v2Home();
-    const systemdUserDir = join(tempHome!, '.config', 'systemd', 'user');
-    await adoptableBrainHome();
-    await program().parseAsync(['node', 'mosaic', 'fleet', 'install', '--no-enable']);
-    // Control: the override is present before the brain home is removed, so a
-    // passing assertion below cannot come from it never having been written.
-    expect(await effectiveConditionPaths(systemdUserDir)).toHaveLength(1);
-    expect((await effectiveConditionPaths(systemdUserDir))[0]).toContain('.mosaic/fleet/agents');
-
-    await rm(join(tempHome!, '.mosaic'), { recursive: true, force: true });
-    await program().parseAsync(['node', 'mosaic', 'fleet', 'install', '--no-enable']);
-
-    const rendered = (await effectiveConditionPaths(systemdUserDir)).map((value): string =>
-      value.replace('%h', tempHome!).replace('%i', 'coder0'),
-    );
-    expect(rendered).toEqual([join(mosaicHome, 'fleet', 'agents', 'coder0.env.generated')]);
+    expect(rendered).toBe(join(mosaicHome, 'fleet', 'agents', 'coder0.env.generated'));
   });
 
   it('guards a real failure — the launcher rejects an absent generated env', async (): Promise<void> => {

packages/mosaic/src/commands/fleet.ts

@@ -13,7 +13,7 @@ import {
 import { randomUUID } from 'node:crypto';
 import { homedir, hostname, userInfo } from 'node:os';
 import { dirname, join, resolve } from 'node:path';
-import { brainHomeIsActive, fleetAgentEnvDir } from '../fleet/brain-home.js';
+import { fleetAgentEnvDir } from '../fleet/brain-home.js';
 import { fileURLToPath } from 'node:url';
 import { spawn } from 'node:child_process';
 import * as readline from 'node:readline';
@@ -2350,80 +2350,6 @@ export function registerFleetAgentCommands(
     });
 }
 
-/** Directory holding the install-managed drop-ins for `[email protected]`. */
-export function agentUnitDropInDir(systemdUserDir: string): string {
-  return join(systemdUserDir, '[email protected]');
-}
-
-/** The one drop-in `mosaic fleet install` owns: the brain-home env condition. */
-export function agentUnitBrainHomeDropInPath(systemdUserDir: string): string {
-  return join(agentUnitDropInDir(systemdUserDir), '10-brain-home.conf');
-}
-
-/**
- * Drop-in re-pointing the agent unit's env condition at the resolved brain home.
- *
- * The shipped unit gates on `%h/.config/mosaic/fleet/agents/%i.env.generated`,
- * which is right for a legacy single-tree install. When a brain home is active
- * (canon `docs/STRUCTURE-CANON.md` §2) the reconciler writes seat env under the
- * brain home instead, so that condition can never be met — and an unmet
- * condition is reported as success (`ConditionResult=no`, `Result=success`,
- * `ExecMainStatus=0`). `fleet start` therefore returns 0, prints nothing, and
- * starts no seat, with every status surface agreeing the fleet is healthy
- * (#1310, measured on mosaic-sbx-dev 1124 against 0.0.50-next.2507).
- *
- * An empty `ConditionPathExists=` resets the inherited list before the correct
- * path is added, so the shipped condition is replaced rather than joined — two
- * conditions would both have to pass and the seat would stay skipped.
- *
- * The boot-window behaviour the shipped unit documents is deliberately kept:
- * this still gates on the generated env existing, only at the path that
- * actually receives it. The launcher already resolves the brain home itself,
- * so nothing downstream of the condition needs to change.
- */
-export function renderAgentUnitBrainHomeDropIn(agentEnvDir: string): string {
-  return [
-    '# Managed by `mosaic fleet install`. Do not edit; re-run install to update.',
-    '#',
-    '# Re-points the seat env condition at the active brain home. Without this the',
-    '# shipped config-home condition can never be met on a split install and every',
-    '# seat is silently skipped while `fleet start` reports success (#1310).',
-    '[Unit]',
-    'ConditionPathExists=',
-    `ConditionPathExists=${join(agentEnvDir, '%i.env.generated')}`,
-    '',
-  ].join('\n');
-}
-
-/**
- * Write the brain-home drop-in when a brain is active, and remove a stale one
- * when it is not.
- *
- * The removal arm is load-bearing, not tidiness: a host that had a brain home
- * and no longer does would otherwise keep a condition pointing at a path the
- * reconciler has stopped writing, which fails in exactly the same silent
- * direction as the bug this fixes.
- */
-export async function syncAgentUnitBrainHomeDropIn(
-  systemdUserDir: string,
-  mosaicHome: string,
-): Promise<void> {
-  const dropInPath = agentUnitBrainHomeDropInPath(systemdUserDir);
-  if (!brainHomeIsActive(mosaicHome)) {
-    try {
-      await unlink(dropInPath);
-    } catch (error) {
-      // Absent is the expected state on a legacy install; anything else is real.
-      if ((error as NodeJS.ErrnoException).code !== 'ENOENT') {
-        throw error;
-      }
-    }
-    return;
-  }
-  await mkdir(agentUnitDropInDir(systemdUserDir), { recursive: true });
-  await writeFile(dropInPath, renderAgentUnitBrainHomeDropIn(fleetAgentEnvDir(mosaicHome)), 'utf8');
-}
-
 async function installFleet(cmd: Command, frameworkRoot: string): Promise<void> {
   const activePaths = resolveFleetPaths(cmd.opts<{ mosaicHome: string }>().mosaicHome);
   assertDefaultMosaicHomeForSystemd(activePaths.mosaicHome);
@@ -2484,9 +2410,6 @@ async function installFleet(cmd: Command, frameworkRoot: string): Promise<void>
     join(frameworkRoot, 'systemd', 'user', '[email protected]'),
     join(activePaths.systemdUserDir, '[email protected]'),
   );
-  // Must follow the copy: the drop-in overrides the unit just written, and on a
-  // split install the unit alone gates every seat on a path nothing writes.
-  await syncAgentUnitBrainHomeDropIn(activePaths.systemdUserDir, activePaths.mosaicHome);
   await copyFile(
     join(frameworkRoot, 'systemd', 'user', '[email protected]'),
     join(activePaths.systemdUserDir, '[email protected]'),