feat(ontology): add Cohort Discovery rule deletion, fix stale URIs and SWRL raw-editor sync

[benoitcayladbx]

Reopened against 0.9.0 after develop was deleted. GitHub cannot reopen #148 (closed PR + missing base), so this is a successor of #148 with the same commits. Original author: @jeremiaspf. Please rebase onto current 0.9.0 before review — expect conflicts.

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What

Three unrelated fixes in the Ontology Designer's Cohort Discovery, Expressions & Axioms, and SWRL screens, grouped together because they're small and touch neighboring code.

Cohort Discovery had no way to delete a rule from the UI. The backend delete endpoint already existed; query-cohorts.js gets _syncDeleteBtn/deleteActiveRule and _ontology_cohorts.html gets the "Delete rule" button (next to "Save rule", disabled until a rule is loaded) to actually call it.

Cohort Discovery also had the same stale-URI problem described in the reasoning/generation PRs, but more visibly: nothing on this screen reconstructed a class/property URI from its current Base URI, so a re-based domain could make an apparently correctly-configured rule show 0 members/0 edges with no obvious cause. Adds base-URI tracking and a _currentUri() helper, used everywhere the screen previously read uri/iri/id directly (class selection, lookup-by-URI, available data properties, compatible relationship properties between two entities, each hop's dropdown).

Expressions & Axioms editor now prefers an element's simple name over its stored URI when populating class/property dropdowns (previously the reverse). The backend (OntologyGenerator._resolve_uri, see the companion generation PR) already rebuilds the correct URI from a simple name against the current Base URI — sending the name instead of a potentially-stale URI avoids axioms carrying a stale URI forward in the first place.

SWRL rule editor: the entity filter for the rule graph now also includes direct subclasses of entities that participate in a business relationship, even when the subclass itself has none — previously such a subclass couldn't be referenced or typed against in a rule, despite being a reasonable thing to do. The raw-text editor's auto-sync from the visual graph selection is now suppressed while the editor is in raw mode, so typing an atom with no corresponding graph node (e.g. a derived class in a THEN clause) is no longer silently overwritten. Also switches the D3.js CDN to jsdelivr (same change as the companion frontend PR — this file needed other edits too, so it's included here rather than split further).

Why

The delete-rule gap and the stale-URI issue both make Cohort Discovery awkward to actually use day to day. The axioms/SWRL fixes are UX papercuts that were easy to fix alongside the above while in the same area of the codebase.

How to test

1. Create a Cohort Discovery rule, save it, then use the new "Delete rule" button — it should remove the rule and the button should be disabled again with no rule loaded.
2. Rename a domain's Base URI after creating classes/relationships used in a Cohort rule — before this fix, the rule shows 0 members/edges; after, it resolves correctly.
3. Save an axiom in Expressions & Axioms referencing a class, rename the domain's Base URI, reopen the editor — the dropdown should still resolve the class correctly.
4. In the SWRL editor, reference a subclass with no relationships of its own in a rule — it should now appear in the graph. Switch to raw-text mode and type an atom with no matching graph node — it should no longer get overwritten by the visual sync.