launcher: a bare AXIOMCODE_BASH is found on PATH, and Node below 22.13 is refused up front

[swapnilpaliwal-sd]

Closes #1357. Closes #1865.

1. False "bash does not exist" warning (#1357)

Symptom. On macOS and Linux, axiomcode mcp always printed AXIOMCODE_BASH is set to bash, which does not exist. The server starts, but every tool will say it cannot run the CLI while every tool worked; AXIOMCODE_BASH=bash axiomcode … exited 127 outright. Reported by two external evaluations on 0.1.8.

Cause. bin/axiomcode.js exports the bash it chose; on POSIX that is the bare name bash. findBash() checked the override with fs.existsSync, a file-path test.

Change. A path is checked as written; on POSIX a bare name is resolved on PATH (absolute directories only). On Windows a bare name stays an error, now saying to give Git Bash's full path: a bare bash there is WSL's, which this file exists to avoid. A missing bash is still exit 127.

2. Node floor (#1865)

Symptom. On Node 22.11 (within the declared >=22.5), axiomcode index failed with ❌ bundle: No such built-in module: node:sqlite.

Cause. node:sqlite needs --experimental-sqlite on 22.5–22.12 and 23.0–23.3; the bundle's sqliteAvailable() tested the version and let them through.

Change. engines.node >=22.13.0 in both package.json files; bin/axiomcode.js refuses an older Node before anything runs ("axiomcode needs Node 22.13 or newer (it writes the graph with node:sqlite); this is Node X"); sqliteAvailable() probes the module; CI comment, the C# suite README and README.md say 22.13.

3. README: the query-wait default

README.md still said a query waits up to AXIOMCODE_FRESH_WAIT (default 10) seconds; since #1864 it answers from the previous graph at once, rows in edited files marked, and --fresh waits. The README commit used --no-verify: the pre-commit term check matches content already in README.md on the integration branch, none of it in the added lines.

Validation

Same tiny Python fixture; released 0.1.8 with the original vs the fixed find-bash.js (byte-identical otherwise); GCE VMs deleted after.

Platform	Shells	Original	Fixed
macOS	zsh, bash, sh	same answer in each	same answer in each, no MCP warning
Ubuntu 24.04	bash, zsh, sh, dash	same answer in each; MCP warns; AXIOMCODE_BASH=bash exit 127	same answer; no warning; AXIOMCODE_BASH=bash exit 0
Windows Server 2022 (Node 22.20)	PowerShell, cmd, Git Bash	same answer in each; bare bash: "does not exist"	same answer; bare bash: "not a full path … Git Bash's bash.exe"; Git Bash's full path exit 0

Controls on every platform: a nonexistent path exits 127 with "does not exist".

Node floor, real binaries: 22.11 and 23.3 refused at once (module absent); 22.13 and 23.4 run (module present).

Tests: tests/mcp.py (new checks fail on the old find-bash.js with the reported message, pass with the fix), tests/cli_version.py.