[CG-09] Configurable filters and metrics in the Code City

[jgrodziski]

Priority: P1
Owner: —

Context

Principle agreed: never manipulate the city itself — only filter its input data. One view = one question / one observation.

Description

In the UI, let the user pick:

• Entity types shown
• Edge types: everything by default; otherwise invocation only, declaration, import, argument declaration, variable declaration… (edge kinds are language-dependent)
• Metric per dimension — width, height, colour: lines of code, cyclomatic complexity, number of attributes / operations, code churn (red on hot spots by default)

Ship a set of default views, each answering one question.

Acceptance criteria

• Entity-type and edge-type selectors
• Width / height / colour each bound to a selectable metric
• At least 3 named default views

---

Source: CodeGraph backlog extracted from the 2026-09-21 weekly (David / Jérémie).