fix: a zoom level that cannot render says so, instead of looking stuck

[lex00]

Closes #131.

Four of the six zoom levels can legitimately render empty, or identically to the level below, and none of them said which. Someone stepping through the picker saw the same picture repeatedly and reported the control as stuck. The views were right; the silence was not.

Nothing here becomes an error

logical on a k8s estate is correctly empty (#74 — the projection's headline kinds are literal AWS::*). composites with no component ownership is correctly the resource graph (#138). These are captioned, not fixed, because there is nothing wrong with them to fix.

Deliberately not a RouteError: those replace the canvas with a card and exist for a view that could not be produced at all. These were produced and are honest — they need a caption, not an error screen.

How it works

src/zoom-notes.ts is pure and reads the finished IR, so a note describes what was actually rendered rather than what the request asked for. The SPA never infers a note; it only displays meta.note.

Composites needs one extra input — how many component edges attached — because that is not recoverable from the IR afterwards: an estate can have zero edges either way (fountain-ops#84). addCompositeDepsCounted reports it, and the silent catch that swallowed a missing component DAG now records the zero instead of shrugging:

         } catch {
-          /* component DAG unavailable — leave composites as-is */
+          /* component DAG unavailable — leave composites as-is, and say so */
+          compositeEdgesAttached = 0;
         }

The second note

Orthogonal to the zoom: a graph with nodes and no edges lays out as a single flat row, which reads as a broken renderer rather than as an accurate picture of a project that declares no references. components and logical are exempt — both lay themselves out (waves, nested boxes), so edge count is not a meaningful judgement of either.

Verified against a live estate

fountain-ops on k3d, pure k8s, serve --env local:

  zoom         nodes edges  note
  logical        0n  0e   logical is an AWS projection — no AWS resources in this estate
  components     5n  4e   (no note)
  composites    11n  0e   no component ownership to join — showing the resource graph
                          unchanged · no edges — nothing in this estate references anything else
  resources     11n  0e   no edges — nothing in this estate references anything else
  attributes    11n  0e   no edges — nothing in this estate references anything else
  runtime       15n  0e   no edges — nothing in this estate references anything else

components stays silent because it renders what it promises — which is the control case that proves the notes are conditional rather than decorative.

just check: tsc clean, 455 tests pass (15 new), build clean.

Scope

This resolves the reported symptom without waiting on any of the projections it describes — #138, #74, chant#1489 and chant#1493 all remain open and all now announce themselves in the UI instead of looking like a dead control.

🤖 Generated with Claude Code

https://claude.ai/code/session_012n8PKN49z8c6jZVA9QYwvk