fix: INHERITS edges missing for Java extends+implements

[loaychlih]

Problem

extract_base_classes() in internal/cbm/extract_defs.c had two bugs
that caused most INHERITS edges to be missing for Java (and likely other
languages using similar AST field names).

Bug 1 — Early return loses multiple inheritance targets

The field loop returned immediately on the first match:

for (const char **f = fields; *f; f++) {
    TSNode super = ts_node_child_by_field_name(node, *f, ...);
    if (!ts_node_is_null(super)) {
        return make_single_base(...);  // ← returns here, never checks interfaces
    }
}

For class Foo extends Bar implements Baz, it found superclass → returned
immediately → never processed super_interfaces. Result: 1 edge instead of 2.

Bug 2 — cbm_node_text returns full node text including keywords

Calling cbm_node_text on the superclass field node returned
"extends Bar" instead of "Bar". On super_interfaces it returned
"implements Baz, Qux" instead of the individual names.

Fix

Added collect_bases_from_field() which:

• Walks into child AST nodes to extract type_identifier / generic_type /
  qualified_name text directly (skips keyword nodes like extends/implements)
• Handles type_list / interface_type_list children for multiple interfaces
• Strips generic args at < (e.g. List<String> → List)
• Falls back to raw cbm_node_text for languages where the field IS the type name

The field loop now collects from all matching fields before returning.

Result

Tested on Modelio
(Java codebase, 253 files):

	Before	After
INHERITS edges	3	116

Example edges now correctly emitted:

• DefaultLinkTool → DefaultDiagramTool (extends)
• DefaultLinkTool → ILinkTool (implements)

[DeusData]

Thanks @loaychlih — clean diagnosis (two distinct bugs in the same function, with a nice repro on Modelio showing 3 → 116 INHERITS edges) and a bounds-safe fix that drops in cleanly alongside the existing arena-pool pattern in this file. Verified: max writes ≤ MAX_BASES_MINUS_1 with the per-iteration count < out_cap checks, no new system/network/file calls, the count == 0 fallback correctly preserves behavior for non-Java grammars where the field IS the type name. Merging now and pushing a small follow-up that adds a regression test for the extends+implements case so this doesn't silently regress.