[codex] Rebaseline Electrobun docs after WGPU release

[devallibus]

Summary

This PR rebaselines the public Electrobun narrative after the upstream WGPU release and the milestone work that has already landed in gametau.

The immediate user-facing problem was that the repository still described Electrobun support in ways that were true before March 4, 2026 but are now stale. In practice that made the README and changelog lag the actual shipped product surface: scaffold/runtime auto-detection exists, create-gametau --desktop-shell electrobun exists, and the repo already contains BrowserWindow and GPUWindow example lanes.

Root cause

The original Electrobun evaluation language was written while WGPU support was still an upstream dependency and before the milestone work merged. The implementation moved forward through issues like #160, #161, #102, and PR #167, but the public docs still used older framing such as "experimental runtime" and "future upstream" style wording.

Fix

This diff updates the public-facing docs that are actually part of the GitHub repo history:

• README.md now describes Electrobun as an explicit supported shell path rather than an abstract experimental provider path.
• The Electrobun support section now distinguishes shipped functionality from remaining release follow-up work.
• The roadmap text now points reviewers at the still-relevant follow-up items instead of upstream blockers that have already been passed.
• CHANGELOG.md now records the earlier alpha/Electrobun work as historical context rather than current-state messaging.

I also aligned the local-only decision note in docs/ELECTROBUN-INTEGRATION-DECISION.md in my workspace, but /docs is ignored in this repository and is therefore not part of the reviewable GitHub diff.

Validation

This is a docs-only change. Validation for this PR was:

• git diff --check
• targeted repo searches to confirm the stale Electrobun wording was removed from the public docs touched here

Milestone context

Refs #159.

After reviewing the current implementation against the issue bodies, #99 and #127 also appear satisfied by already-merged work, but I left issue closure out of this PR so the review stays scoped to the doc rebaseline.

[devallibus]

PR Review — claude-opus-4-6 (Claude Opus 4.6, 1M context)

Overall

Clean docs-only rebaseline. 8 additions, 6 deletions across 2 files. Every change replaces stale framing with language that matches the actual shipped state.

Verdict: Approve. No issues.

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Changes reviewed

CHANGELOG.md — The v0.5.0 entry's "Experimental Electrobun runtime" phrasing is replaced with "Initial Electrobun runtime spike as an opt-in alpha path" and adds forward context noting this baseline was later expanded by v0.7.0. Accurate — the changelog now reads as historical context rather than current-state messaging.

README.md — 5 targeted edits:

1. "for experimental runtimes" → "for provider-backed runtimes such as Electrobun" — Correct. Electrobun is no longer experimental; it's a named, shipped provider path.

2. "Electrobun desktop bootstrap helpers (experimental)" → "...for explicit BrowserWindow and GPUWindow shell paths" — Removes the stale "experimental" label and adds specificity about what the adapter actually covers.

3. Roadmap status paragraph — Drops the generic "Update:" prefix and anchors to the March 6, 2026 date. Shifts framing from "Electrobun now ships..." (which reads as a changelog entry) to "As of [date], gametau ships..." (which reads as current state). The remaining work list correctly identifies it as gametau-internal follow-through, not upstream-blocked.

4. "What's not yet done" → "Remaining follow-up work" — Better tone. The old heading implied incompleteness; the new one frames it as planned next steps.

5. New paragraph linking historical upstream-blocked issues ([P1] Sync Electrobun BrowserWindow baseline into repo #98, [P1] Win11 GPUWindow capability gate + counter proof #100, [P1] Add Win11-first GPUWindow CI smoke lane #104, [BLOCKER] Electrobun npm releases lack GpuWindow/WebGPU exports #106) and pointing to active milestone tracking ([P0] Rebaseline Electrobun roadmap/docs now that WGPU shipped upstream #159, Tracking: Electrobun WGPU first-class support for v0.7.0 #162) — Good for reviewers who encounter those old issues and need orientation.

6. Roadmap section header "shipped → next steps" → "shipped → release follow-up" — More precise about where the work sits.

Observations

• The PR body correctly notes that docs/ELECTROBUN-INTEGRATION-DECISION.md was aligned locally but isn't in the diff because /docs is gitignored. No action needed.
• Leaving [P2] create-gametau runtime option for Electrobun GPUWindow #99 and Experimental Electrobun: auto-detect runtime in scaffold and examples before falling back to WASM #127 open for separate closure is the right scoping call for a docs PR.
• No whitespace issues, no broken links, no formatting regressions.

LGTM — ready to mark non-draft when you're satisfied.

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Reviewed by claude-opus-4-6 (Claude Opus 4.6, 1M context)