chore: keep ISSUE-*.md task notes local

Local task notes (ISSUE-*.md at the repo root) are for local use only: they
are git-ignored and never referenced from committed files.

Changes:
- .gitignore: ignore ISSUE-*.md
- AGENTS.md: local issues are git-ignored and never committed
- docs/arc42/11-risks-and-technical-debt.md: drop the local-notes debt item

Tests: repository hygiene only; git check-ignore confirms the files are
ignored.

Author: kvs-coder

.gitignore

@@ -93,3 +93,6 @@ library/libs/*.aar
 
 # IDE state
 .idea/
+
+# Local task notes, not for the repository
+ISSUE-*.md

AGENTS.md

@@ -366,7 +366,7 @@ Refs: #<issue>
 * `Refs: #<issue>` is required whenever an issue exists.
 
 ### Local Issues
-Work not yet on GitHub lives in `ISSUE-<slug>.md` files at the repo root, titled with the Conventional Commit header the work will ship under. File one on GitHub with the `github-create` skill (or `gh issue create --body-file ISSUE-<slug>.md`), then delete the local file in the PR that references it.
+Work not yet on GitHub lives in `ISSUE-<slug>.md` files at the repo root, titled with the Conventional Commit header the work will ship under. They are for local use only: git-ignored, never committed or referenced from committed files. File one on GitHub with the `github-create` skill (or `gh issue create --body-file ISSUE-<slug>.md`) when it should become public.
 
 ---
 

docs/arc42/11-risks-and-technical-debt.md

@@ -22,4 +22,3 @@
 | `Exercise` sessions drop `swimmingLog` | `model/payload/Exercise.kt` | Model `SwimmingLog` / `SwimmingInterval` |
 | No callback / `CompletableFuture` façade for Java and Flutter channel code | `service/` | Thin layer over the suspend API (ADR 0002) |
 | CI actions still target Node.js 20 (deprecation annotations) | `.github/workflows/` | Bump `actions/checkout`, `setup-java`, `upload-artifact`, `gradle/actions` to Node 24 versions |
-| Local `ISSUE-*.md` files at the repo root | repo root | File remaining items on GitHub, delete the files |