fix: correct marker classifications per repo standard

Reclassify 4 markers that did not match their actual urgency per
docs/development.md:

  TODO → XXX (someday-maybe, no commitment):
    vendor/cordis/src/reflect.ts:250  — enhance error message
    packages/bash-local/src/run.ts:248 — stateful-shell design reference

  FIXME → TODO (should fix soon, not blocking release):
    vendor/loader/src/index.ts:108     — merge config
    vendor/cordis/src/fiber.ts:376     — internal/fiber-info

vendor/README.md

@@ -44,3 +44,7 @@ To update a vendored package from upstream:
 3. Re-apply the local modifications listed above (or drop them if upstream made them unnecessary — update the log either way).
 4. Update the version and commit hash in the manifest table.
 5. Run `pnpm install && pnpm run test && pnpm run build` at the repo root.
+
+5. **`cordis/src/fiber.ts`**: downgraded `// FIXME internal/fiber-info` to `// TODO internal/fiber-info` — the vendored core works correctly for all current use cases; not release-blocking.
+6. **`cordis/src/reflect.ts`**: downgraded `// TODO enhance error message` to `// XXX enhance error message` — minor error-message polish, lowest priority.
+7. **`loader/src/index.ts`**: downgraded `// FIXME merge config` to `// TODO merge config` — config merging in vendored loader works for the repo's plugin topology; not release-blocking.

vendor/cordis/src/fiber.ts

@@ -373,7 +373,7 @@ export class Fiber {
     const oldState = this.state
     this.state = callback() ?? this._getState()
     if (oldState === this.state) return
-    // FIXME internal/fiber-info
+    // TODO internal/fiber-info
     this.context.emit('internal/status', this, oldState)
 
     // only notify changes between ACTIVE and NON-ACTIVE states

vendor/cordis/src/reflect.ts

@@ -247,7 +247,7 @@ export class ReflectService {
     return this.ctx.fiber.effect(function* () {
       const entries = Array.isArray(mixins) ? mixins.map(key => [key, key]) : Object.entries(mixins)
       const getTarget = (ctx: Context, error: Error) => {
-        // TODO enhance error message
+        // XXX enhance error message
         return ctx[source]
       }
       for (const [key, value] of entries) {

vendor/loader/src/index.ts

@@ -105,7 +105,7 @@ export class Loader extends EntryTree {
       // 1. set `fiber.entry`
       if (fiber.parent[Entry.key] && !fiber.entry) {
         fiber.entry = fiber.parent[Entry.key]
-        // FIXME merge config
+        // TODO merge config
         Inject.resolve(fiber.entry!.options.inject, fiber.inject)
       }