feat(wiki): [[wikilinks]] with redlinks + cross-project resolver (Issue B)

Last P2 from Antoine's "daily-usable" sprint. Entities referenced via
[[Name]] in descriptions or mirror markdown now render as:

- live wikilink if the name matches an entity in the same project
- live cross-project link with "(in project X)" scope indicator if the
  only match is in another project
- red italic redlink pointing at /wiki/new?name=... otherwise

Clicking a redlink opens a pre-filled "create this entity" form that
POSTs to /v1/entities and redirects to the new entity's page.

- engineering/wiki.py: _wikilink_transform + _resolve_wikilink,
  applied in render_project (pre-markdown) and render_entity
  (description body). render_new_entity_form for the create page.
  CSS for .wikilink / .wikilink-cross / .redlink / .new-entity-form
- api/routes.py: GET /wiki/new?name&project
- tests/test_wikilinks.py: 12 tests including the spec regression
  (A references [[B]] -> redlink; create B -> link becomes live)
- DEV-LEDGER.md: session log + test_count 521 -> 533

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

tests/test_wikilinks.py

@@ -0,0 +1,132 @@
+"""Issue B — wikilinks with redlinks + cross-project resolution."""
+
+import pytest
+from fastapi.testclient import TestClient
+
+from atocore.engineering.service import (
+    create_entity,
+    init_engineering_schema,
+)
+from atocore.engineering.wiki import (
+    _resolve_wikilink,
+    _wikilink_transform,
+    render_entity,
+    render_new_entity_form,
+    render_project,
+)
+from atocore.main import app
+from atocore.models.database import init_db
+
+
+@pytest.fixture
+def env(tmp_data_dir, tmp_path, monkeypatch):
+    registry_path = tmp_path / "test-registry.json"
+    registry_path.write_text('{"projects": []}', encoding="utf-8")
+    monkeypatch.setenv("ATOCORE_PROJECT_REGISTRY_PATH", str(registry_path))
+    from atocore import config
+    config.settings = config.Settings()
+    init_db()
+    init_engineering_schema()
+    yield tmp_data_dir
+
+
+def test_resolve_wikilink_same_project_is_live(env):
+    tower = create_entity(entity_type="component", name="Tower", project="p05")
+    href, cls, _ = _resolve_wikilink("Tower", current_project="p05")
+    assert href == f"/wiki/entities/{tower.id}"
+    assert cls == "wikilink"
+
+
+def test_resolve_wikilink_missing_is_redlink(env):
+    href, cls, suffix = _resolve_wikilink("DoesNotExist", current_project="p05")
+    assert "/wiki/new" in href
+    assert "name=DoesNotExist" in href
+    assert cls == "redlink"
+
+
+def test_resolve_wikilink_cross_project_indicator(env):
+    other = create_entity(entity_type="material", name="Invar", project="p06")
+    href, cls, suffix = _resolve_wikilink("Invar", current_project="p05")
+    assert href == f"/wiki/entities/{other.id}"
+    assert "wikilink-cross" in cls
+    assert "in p06" in suffix
+
+
+def test_resolve_wikilink_case_insensitive(env):
+    tower = create_entity(entity_type="component", name="Tower", project="p05")
+    href, cls, _ = _resolve_wikilink("tower", current_project="p05")
+    assert href == f"/wiki/entities/{tower.id}"
+    assert cls == "wikilink"
+
+
+def test_transform_replaces_brackets_with_anchor(env):
+    create_entity(entity_type="component", name="Base Plate", project="p05")
+    out = _wikilink_transform("See [[Base Plate]] for details.", current_project="p05")
+    assert '<a href="/wiki/entities/' in out
+    assert 'class="wikilink"' in out
+    assert "[[Base Plate]]" not in out
+
+
+def test_transform_redlink_for_missing(env):
+    out = _wikilink_transform("Mentions [[Ghost]] nowhere.", current_project="p05")
+    assert 'class="redlink"' in out
+    assert "/wiki/new?name=Ghost" in out
+
+
+def test_transform_alias_syntax(env):
+    tower = create_entity(entity_type="component", name="Tower", project="p05")
+    out = _wikilink_transform("The [[Tower|big tower]] is tall.", current_project="p05")
+    assert f'href="/wiki/entities/{tower.id}"' in out
+    assert ">big tower<" in out
+
+
+def test_render_entity_description_has_redlink(env):
+    a = create_entity(
+        entity_type="component",
+        name="EntityA",
+        project="p05",
+        description="This depends on [[MissingPart]] which does not exist.",
+    )
+    html = render_entity(a.id)
+    assert 'class="redlink"' in html
+    assert "/wiki/new?name=MissingPart" in html
+
+
+def test_regression_redlink_becomes_live_once_target_created(env):
+    a = create_entity(
+        entity_type="component",
+        name="EntityA",
+        project="p05",
+        description="Connected to [[EntityB]].",
+    )
+    # Pre-create: redlink.
+    html_before = render_entity(a.id)
+    assert 'class="redlink"' in html_before
+
+    b = create_entity(entity_type="component", name="EntityB", project="p05")
+    html_after = render_entity(a.id)
+    assert 'class="redlink"' not in html_after
+    assert f"/wiki/entities/{b.id}" in html_after
+
+
+def test_new_entity_form_prefills_name():
+    html = render_new_entity_form(name="FreshEntity", project="p05")
+    assert 'value="FreshEntity"' in html
+    assert 'value="p05"' in html
+    assert "entity_type" in html
+    assert 'method="post"' not in html  # JS-driven
+
+
+def test_wiki_new_route_renders(env):
+    client = TestClient(app)
+    r = client.get("/wiki/new?name=NewThing&project=p05")
+    assert r.status_code == 200
+    assert "NewThing" in r.text
+    assert "Create entity" in r.text
+
+
+def test_wiki_new_url_escapes_special_chars(env):
+    # "steel (likely)" is the kind of awkward name AKC produces
+    href, cls, _ = _resolve_wikilink("steel (likely)", current_project="p05")
+    assert cls == "redlink"
+    assert "name=steel%20%28likely%29" in href