fix(make-pdf): Bun.which-based binary resolution for browse + pdftotext on Windows (v1.24 extension)

[scarson]

Summary

On Windows, make-pdf generate fails with browse binary not found even after a successful ./setup. The resolution logic in make-pdf/src/browseClient.ts probes bare paths, but bun build --compile --outfile browse/dist/browse emits browse/dist/browse.exe on Windows, so every probe misses. Same root cause in make-pdf/src/pdftotext.ts:resolvePdftotext.

This is a v1.24-aligned reshape of #1118 (closed in favor of this PR). v1.24.0.0 (#1252) introduced Bun.which() + GSTACK_*_BIN override pattern in browse/src/claude-bin.ts for the claude binary. This PR extends the same pattern to the two other binary resolvers in the codebase: resolveBrowseBin and resolvePdftotext.

Root cause

Two independent issues compound:

1. fs.constants.X_OK is degraded to existence-checking on Windows. Per the Node.js docs on fs.accessSync: fs.accessSync('/path/to/browse', X_OK) on Windows checks whether a file literally named browse (no extension) exists. When bun emits browse.exe, the check returns false. Bun.which() handles this correctly via PATHEXT.

2. bun --compile --outfile appends .exe on Windows unconditionally. The build command targets browse/dist/browse etc.; on Windows, bun silently appends .exe. Confirmed:

$ ls ~/.claude/skills/gstack/{browse,make-pdf,design}/dist/*.exe
browse/dist/browse.exe
make-pdf/dist/pdf.exe
design/dist/design.exe

3. The which browse PATH fallback doesn't help native Windows. which ships with Git Bash but not cmd.exe / PowerShell. Bun.which('browse') works from all three.

Coordination with #1094

@BkashJEE's PR #1094 (still open) covered browseClient.ts independently with a narrower scope (no pdftotext, no tests, no GSTACK_*_BIN naming). This PR's pdftotext fix + cross-platform tests + v1.24-aligned env override naming are additive. Either order of merge works; happy to rebase as a follow-on if #1094 lands first.

What changed from #1118

• GSTACK_BROWSE_BIN / GSTACK_PDFTOTEXT_BIN as the v1.24-aligned overrides; BROWSE_BIN / PDFTOTEXT_BIN remain as back-compat aliases (matching v1.24's GSTACK_CLAUDE_BIN ?? CLAUDE_BIN pattern).
• Bun.which() replaces execFileSync('which', ...) for PATH lookup. No more where-vs-which branch.
• findExecutable(base) helper exported from each module — probes .exe/.cmd/.bat after the bare-path miss on win32. POSIX behavior bit-identical (isExecutable short-circuits before the win32 branch).
• macCandidates → posixCandidates in pdftotext.ts (always was POSIX-only). No Windows candidates added — Poppler scatters across Scoop / Chocolatey / oschwartz10612-poppler-windows; guessing causes false positives. Set GSTACK_PDFTOTEXT_BIN explicitly. Error message gets a Windows install hint (scoop install poppler) and setx example.
• Pre-existing test 'honors BROWSE_BIN when it points at a real executable' was hardcoded /bin/sh — made cross-platform via a REAL_EXE constant (cmd.exe on win32, /bin/sh on POSIX). This was a Windows-CI blocker on its own.

Test plan

• bun test make-pdf/test/browseClient.test.ts make-pdf/test/pdftotext.test.ts on win32 — 29 pass, 0 fail (12 new assertions: findExecutable POSIX/win32-extension-probe/null; resolveBrowseBin GSTACK_BROWSE_BIN + BROWSE_BIN + precedence + quote-strip; same shape for resolvePdftotext + Windows install hint in error message)
• POSIX CI — relying on the existing matrix. POSIX branch returns unchanged behavior; Bun.which('browse') on Linux/macOS resolves via PATH the same way execFileSync('which', 'browse') did, minus the Git Bash dependency.

What this PR doesn't do

• Fix findTelemetryBinary in browse/src/security.ts. Different bug (shebang-script invocation on Windows), different fix — see companion PR fix(browse): bash.exe wrap for telemetry on Windows (v1.24 extension) #1306 (closed fix(browse): wrap telemetry bash script with bash.exe on Windows #1119, reopened against v1.24).
• Enable Windows CI. Already shipped in v1.24.0.0 via windows-free-tests.yml. ✅

🤖 Generated with Claude Code

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