docs(spec): split execution modes from application-profile into job-sandbox-execution

- application-profile keeps the profile core: config, access and submit,
  dispatch record, outer pre/post-exec layer; mode: accepts only direct
- sandbox mode + options, I/O directories, capability advertisement and
  placement by mode move to job-sandbox-execution
- order: application-profile requirements/design before job-config-merge
  design; implementation interleaves

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

.kiro/specs/application-profile/brief.md

@@ -45,6 +45,18 @@ consumed by `service-supervision` (worker probes and restarts),
 `service-endpoint` (ports, endpoints).
 
 **Update 2026-10-12 (discussion; user decisions):**
+- **Split: execution modes move to `job-sandbox-execution`.** This spec is
+  the profile core: config, access and submit, job state (name, dispatch
+  record), the outer pre/post-exec layer. Its schema has `mode:` but
+  accepts only `direct`. The `sandbox` mode with its options, I/O
+  directories, worker capability advertisement and scheduler placement by
+  mode belong to `job-sandbox-execution`, since nothing uses a non-`direct`
+  mode before the sandbox exists. The worker's clear launch error for a
+  missing `direct` exec user stays here.
+- **Order with `job-config-merge`:** requirements and design of this spec
+  first (it fixes the profile schema), then `job-config-merge`'s design;
+  implementation tasks interleave (schema/config, merge library, submit
+  validation and dispatch record).
 - **Own configuration file.** Profiles live in a new
   `src/configs/applications.yaml` with its own JSON schema, mapped into
   `ClusterConfig` and `Conf4Sched` like queues and limits. See "Profile
@@ -144,9 +156,9 @@ fits XCE's LSF-style job model.
 - **Admins define named application profiles** in the cluster configuration. The
   first version contains the following (user decision; the format must be
   extensible for "maybe others"):
-  1. **Execution mode and its options.** `direct` or `sandbox` now, with room for
-     `container`/`vm`. Sandbox options include the allowed input/output
-     prefixes and isolation extras.
+  1. **Execution mode.** The `mode:` field, accepting only `direct` in this
+     spec; `job-sandbox-execution` adds `sandbox` with its options (allowed
+     input/output prefixes, isolation extras), later `container`/`vm`.
   2. **Launch type.** Serial, `openmpi` or `mpich`.
   3. **Environment and pre/post-exec.** Environment variables the application
      needs, and the outer pre/post-exec commands.
@@ -210,9 +222,9 @@ fits XCE's LSF-style job model.
     user doesn't exist on the node, the worker fails the job at launch with a
     clear, user-visible reason, instead of today's opaque systemd failure.
   - Account-less users are served by profiles whose mode is `sandbox`.
-- **Placement.** A job is placed only on workers whose advertised capabilities
-  support its effective mode (sandbox needs systemd 242 or later and
-  `nss-systemd`).
+- **Placement by mode** (moved to `job-sandbox-execution`): a job is placed
+  only on workers whose advertised capabilities support its mode (sandbox
+  needs systemd 242 or later and `nss-systemd`).
 - **Ownership.** The submitter remains the owner for RBAC, limits and accounting
   in every mode.
 
@@ -248,9 +260,9 @@ fits XCE's LSF-style job model.
   launch type, env, profile pre/post-exec) are read from the profile at
   dispatch, as queue pre/post-exec is today (`get_queue_exec()`,
   `controller/queue.c:199`).
-- **Workers advertise their supported execution modes.** The scheduler filters
-  hosts by the job's effective mode. The design picks the mechanism, for example
-  a host attribute or boolean resource.
+- **Workers advertise their supported execution modes** and the scheduler
+  filters hosts by mode: `job-sandbox-execution` (the design picks the
+  mechanism, e.g. a host attribute or boolean resource).
 
 ### Profile configuration
 - **One file per entity type**, as for hosts, queues, resources, limits,
@@ -527,9 +539,13 @@ Decided 2026-10-12 (user), so a rename never strands jobs:
   - RBAC permission for profile use.
   - Submit surfaces: REST, `xcecli --app`, harness, libxce.
   - The profile name and the job's own values persisted on the job.
-  - Execution-mode and I/O-directory fields end to end.
-  - Capability advertisement and placement.
+  - The `mode:` schema field (only `direct`).
   - A worker launch error when a `direct` exec user is missing.
+  - Dispatch record (scheduling and execution values, content hash) and the
+    retryable dispatch failure for a missing or changed profile.
+  - Profile pre/post-exec as the outer layer (moved from the queue), with
+    a clean environment; the reserved `XCE_` prefix.
+  - Aliases, live-upgrade warning, pend reason for a missing profile.
   - Profile name and mode shown in job details.
   - Listing available profiles (REST and xcecli).
   - Profile `--dry-run` support: the effective values a job would get
@@ -552,12 +568,12 @@ Decided 2026-10-12 (user), so a rename never strands jobs:
     the outer layer and reserved `XCE_` instead of an env denylist; moving
     pending jobs deferred to `job-modify`, profile aliases in v1; override granularity (no markers; additive rule),
     limits a job may lower (profile limits are maximums), personal presets
-    (client side), `app:override` and inheritance (deferred).
-    - Splitting the spec: execution mode, I/O directories, capability
-      advertisement and placement as a separate spec (or folded into
-      `job-sandbox-execution`), leaving this spec the profile core.
+    (client side), `app:override` and inheritance (deferred); execution modes
+    split into `job-sandbox-execution`.
 - **Out**:
-  - The worker sandbox mechanics (`job-sandbox-execution`).
+  - The `sandbox` mode and its options, I/O directories, capability
+    advertisement, placement by mode and the worker sandbox mechanics
+    (`job-sandbox-execution`).
   - Multi-node sandbox (`job-sandbox-multinode`).
   - Container or vm execution itself (only room for them in the schema).
   - Auth backends and JWT claims.
@@ -569,7 +585,6 @@ Decided 2026-10-12 (user), so a rename never strands jobs:
 - Submit and listing surfaces (REST, xcecli, harness, libxce).
 - Persisting the profile name and the job's own values (wire, WAL submit
   fact, snapshot).
-- Capability advertisement and scheduler placement.
 
 ## Out of Boundary
 - Worker execution backends and sandbox mechanics.
@@ -587,9 +602,10 @@ Decided 2026-10-12 (user), so a rename never strands jobs:
   - The config pipeline (`clusterconfig-schema-split`, `config-upgrade-snapshot`,
     `admin-config-tool`).
   - RBAC (`rbac_check.go`).
-  - Resource/attribute reporting from worker to scheduler.
 - **Downstream**:
-  - `job-sandbox-execution` consumes the effective mode, options and directories.
+  - `job-sandbox-execution` adds the `sandbox` mode, its options and I/O
+    directories, capability advertisement and placement, on top of this
+    spec's `mode:` field and dispatch record.
   - `job-sandbox-multinode`.
   - Future `container`/`vm` modes, which add profile attributes.
   - `job-status-detail-display`, which can show the profile and mode.
@@ -618,6 +634,6 @@ Decided 2026-10-12 (user), so a rename never strands jobs:
 - Input validation (`security.md`): the job's additions and paths are validated
   server-side. No path traversal, and mount prefixes are restricted by the
   profile.
-- Size: this is likely 20 or more tasks. If requirements confirm that, split
-  as listed under "Open for requirements".
+- Size: still large after the split (config, access and submit, job state,
+  outer layer); one coherent feature, testable end to end with `direct`.
 - HA/persistence spec: use the full 3-phase workflow.