check:claude-md fails on two broken instruction-file links under docs/media

**Found by** the PR gauntlet on #4275 (`fix/4260-new-user-roles-default`), 2026-09-07. Not caused by that PR: neither file is in its diff; pre-existing at `f2ec156daf31670b42d7704e994686b09daf14df`.

### Where
`docs/media/FORMS_ARCHITECTURE_GUIDE.md` → `../packages/Angular/CLAUDE.md`
`docs/media/PREDICTIVE_STUDIO_GUIDE.md` → `../migrations/CLAUDE.md`

### What happens
```
$ pnpm run check:claude-md
· docs/media/FORMS_ARCHITECTURE_GUIDE.md: points at instruction file ../packages/Angular/CLAUDE.md, which does not exist
· docs/media/PREDICTIVE_STUDIO_GUIDE.md: points at instruction file ../migrations/CLAUDE.md, which does not exist
ELIFECYCLE Command failed with exit code 1.
```
Both targets exist; the relative paths are wrong for a file living under `docs/media/`. From there, `../` reaches `docs/`, not the repo root, so the links need one more `../`.

### Why it matters
Small in itself, but it is one of the repo's documented local CI mirrors (`npm run check:claude-md` — "instruction-file budget, link validity, and routing-table coverage"). A gate that is red for unrelated reasons stops being a signal: the next person to break a genuine instruction-file link will see a failure that looks like the one everybody already ignores.

### Repro
```bash
cd ~/Projects/mj-dev/MJ && pnpm run check:claude-md
```

### Evidence
The command output above, from a clean checkout of the merge of this PR with `next`.

### Suggested fix
Correct the two relative paths (`../packages/Angular/CLAUDE.md` → `../../packages/Angular/CLAUDE.md`, and likewise for the migrations link). Verify the rest of `docs/media/` for the same one-level-off mistake while there, since it is likely systematic — these two files were probably moved into `docs/media/` without their links being re-based.

### Definition of done
- [ ] `pnpm run check:claude-md` exits 0
- [ ] Both links resolve to the real instruction files
- [ ] No other file under `docs/media/` has the same off-by-one relative path
- [ ] Existing suite and gates green; no changed expectation in an existing test

### Verify by
`pnpm run check:claude-md` exiting 0, and clicking through both links on the rendered docs.

Update the links in docs/media/FORMS_ARCHITECTURE_GUIDE.md and docs/media/PREDICTIVE_STUDIO_GUIDE.md, then inspect the other files under docs/media/ for the same path mistake. Run pnpm run check:claude-md and confirm it exits 0, both links resolve, and the existing suite and gates remain green.

Written by the indexing model from the issue text.