Workspace concurrency review iteration: Jobs's 3 taste asks

Closes the three specific_asks from Jobs's T1 review of the workspace
architecture fix (7829acc..15e3863):

1. docs/architecture/workspace-concurrency.md: decision table
   upgraded from a code block to a real Markdown table so it reads
   consistently with the failure-modes table lower in the file.

2. docs/architecture/workspace-concurrency.md + resolve-workspace.ts:
   added "Sunset coding-role inference" section and a TODO marker on
   CODING_ROLE_PATTERN tying the regex to the v52 transition window
   (target 2026-05-20). Both documents now name the end-state
   explicitly so a future engineer knows why the regex exists and
   when it dies.

3. resolve-workspace.ts: enriched the WorkspaceConfigurationError
   message to include taskId / agentId / projectId alongside the
   existing companyId, so a misconfigured setup points operators at
   the offending row instead of just the company.

No behaviour change, no fallback, no mock. typecheck green, 540 unit
tests green, 10 eval tests green.

src/main/orchestration/resolve-workspace.ts

@@ -62,6 +62,16 @@ export class WorkspaceConfigurationError extends Error {
   }
 }
 
+// TODO(post-v52 stabilisation, target 2026-05-20): delete this safety net
+// once every task-creation path sets `requires_filesystem` explicitly.
+// Rationale: during v52 rollout some legacy creators still emit tasks with
+// a null `requires_filesystem`, and a CTO-typed task without the flag
+// would otherwise fall through to lockMode=none and happily write files
+// under no lock. Once seed data + every `db.tasks.saveTask` callsite is
+// audited (tracked in docs/architecture/workspace-concurrency.md
+// "Sunset coding-role inference"), this regex and the rule-2 role branch
+// below both get removed and the column becomes the single source of
+// truth. Do not extend this regex — add columns instead.
 const CODING_ROLE_PATTERN = /cto|engineer|developer|devops|sre/i;
 
 /**
@@ -143,7 +153,7 @@ function inferLockMode(
   }
 
   throw new WorkspaceConfigurationError(
-    `Task requires a filesystem-backed run but no workspace is bound to the task, agent, or project (companyId=${companyId}).`,
+    `Task requires a filesystem-backed run but no workspace is bound to the task, agent, or project (companyId=${companyId}, taskId=${task?.workspaceId === undefined ? "<null-task>" : (task as { id?: string }).id ?? "<unknown>"}, agentId=${(agent as { id?: string }).id ?? "<unknown>"}, projectId=${task?.projectId ?? "<null>"}).`,
   );
 }