app-server-protocol: mark permission profiles experimental (#19899)

## Why

`PermissionProfile` is now the canonical internal permissions
representation, but the app-server wire shape is still intentionally
unstable while the migration continues. Stable app-server clients should
not see or generate code for these fields until the wire format settles.

## What changed

- Marks every app-server v2 field that sends `PermissionProfile` as
experimental, including `command/exec`, `thread/start`, `thread/resume`,
`thread/fork`, and `turn/start` request/response payloads.
- Enables per-field experimental inspection for `command/exec`, so
`permissionProfile` is gated without making the entire method
experimental.
- Fixes the generated TypeScript schema filter to be comment-aware. The
previous scanner treated apostrophes inside doc comments as string
delimiters, so some experimental fields leaked into stable TypeScript
even though stable JSON was filtered correctly.

## Verification

- `cargo test -p codex-app-server-protocol`










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[//]: # (BEGIN SAPLING FOOTER)
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* #19900
* __->__ #19899

codex-rs/app-server-protocol/schema/json/v2/TurnStartParams.json

@@ -829,17 +829,6 @@
     "outputSchema": {
       "description": "Optional JSON Schema used to constrain the final assistant message for this turn."
     },
-    "permissionProfile": {
-      "anyOf": [
-        {
-          "$ref": "#/definitions/PermissionProfile"
-        },
-        {
-          "type": "null"
-        }
-      ],
-      "description": "Override the full permissions profile for this turn and subsequent turns. Cannot be combined with `sandboxPolicy`."
-    },
     "personality": {
       "anyOf": [
         {