Refresh the ECOSYSTEM compatibility matrix for v0.3.0 and spannerplanviz v0.11.0

[apstndb]

Context

ECOSYSTEM.md on both tagged v0.3.0 and current main still says:

As of 2026-07-18

spannerplan tags observed while writing this matrix: latest non-prerelease v0.2.1; prerelease v0.3.0-alpha.2

The consumer table still lists spannerplanviz at v0.10.2 requiring spannerplan v0.2.0.

Published reality:

• spannerplan latest non-prerelease is v0.3.0.
• spannerplanviz v0.11.0 (2026-07-22) requires github.com/apstndb/spannerplan v0.3.0 and go 1.25.0 (go.mod of that tag). Release notes for v0.11.0 state the Go 1.25 floor came from security-fixed golang.org/x/image / x/text.
• execspansql now consumes both libraries at those versions (go 1.25.0, spannerplan v0.3.0, spannerplanviz v0.11.0).
• spanner-mycli v0.34.2 and main already pin spannerplan v0.3.0 (PR build: adopt spannerplan v0.3.0 spanner-mycli#814).

The matrix is generated from ecosystem/matrix.json. Leaving it on v0.2.1 / v0.10.2 after the v0.3.0 train shipped makes the canary and downstream pin checklist point at the previous train.

Verified against github.com/apstndb/spannerplan@v0.3.0, GitHub main ECOSYSTEM.md, and spannerplanviz@v0.11.0. No existing issue.

Request

Refresh ecosystem/matrix.json and regenerate ECOSYSTEM.md:

• Record spannerplan latest non-prerelease as v0.3.0.
• Record spannerplanviz v0.11.0 → spannerplan v0.3.0, and note the Go 1.25 module floor on spannerplanviz.
• Update observed spanner-mycli / rendertree-web / spannerplan-rs pins if they have moved.
• Consider adding execspansql as a library consumer (spannerplan v0.3.0, spannerplanviz v0.11.0 at apstndb/execspansql@ff4f7d1).

Alternatives considered

• Leave the matrix as a historical snapshot of 2026-07-18. The document presents itself as the current observed-pin table and is what release checklist / canary consumers read.
• Only bump the date without recording v0.11.0 / Go 1.25. That would still hide the floor that downstream go 1.24 modules cannot take.

Downstream evidence

execspansql PRs #94 (adopted spannerplan v0.3.0 / spannerplanviz v0.11.0) and #95 (plan JSON/YAML artifact intended as ecosystem interchange). Merged at ff4f7d1.