fix(install): skip extension-v* releases when picking latest CLI

[George-iam]

Why

A user trying to install on a fresh box just now:

```
$ curl -fsSL https://raw.githubusercontent.com/AxmeAI/axme-code/main/install.sh | bash
Detected platform: linux-x64
Fetching latest release...
Installing axme-code extension-v0.1.5 (linux-x64)...
curl: (22) The requested URL returned error: 404
```

The installer picked the wrong tag: extension-v0.1.5 instead of v0.6.0. Then tried to download axme-code-linux-x64 from a release that only contains .vsix files → 404.

Root cause

We publish two parallel release tracks from this repo:

Tag pattern	What ships
v*	CLI binary releases (6 platform-specific files)
extension-v*	VS Code / Cursor extension .vsix bundles (5 platform-specific files)

install.sh:30 and install.ps1:29 both hit /releases/latest, which returns the most-recently-published release across ALL tags. Today's release order — v0.6.0 at 09:25 UTC, then extension-v0.1.5 at 09:30 UTC — made the extension release "latest" 8 hours ago. Every fresh curl|bash install.sh call has 404'd since.

The bug has existed since we added the extension release track but only triggers when we publish in the order "CLI release first, then extension release." In v0.5.0 era we published extension releases before the CLI release (extension-v0.1.4 → v0.5.0 was reversed) so the issue was masked.

Fix

Switch both installers from /releases/latest to /releases?per_page=30 and filter for the first tag_name matching ^v[0-9]:

• install.sh: curl ... | grep tag_name | sed ... | grep -E '^v[0-9]' | head -1
• install.ps1: Invoke-RestMethod ... | Where-Object { $_.tag_name -match '^v[0-9]' } | Select-Object -First 1

Both pieces of logic carry a code comment explaining the two-track release model and the failure case so the next operator doesn't re-introduce it.

Verified

Dry-runned against the live API:

```bash
$ curl -fsSL "https://api.github.com/repos/AxmeAI/axme-code/releases?per_page=30\" \
| grep '"tag_name"' \
| sed 's/.*"tag_name": "//;s/".//' \
| grep -E '^v[0-9]' | head -1
v0.6.0
```

Workaround until this merges

End users can still install by passing the version explicitly:

```bash
curl -fsSL https://raw.githubusercontent.com/AxmeAI/axme-code/main/install.sh | bash -s v0.6.0

install.ps1: iwr ... | iex -ArgumentList v0.6.0

```

(Both installers already accept the version as the first positional argument — install.sh:56, install.ps1:60.)

After merge

No tag, no release needed. install.sh and install.ps1 are served via raw.githubusercontent.com/AxmeAI/axme-code/main/install.sh — the next curl|bash after merge will pick up the fix.

Test plan

• AST/syntax: bash -n install.sh clean (no parse error introduced)
• Live-API dry-run resolves to v0.6.0 correctly
• After merge: another curl|bash install.sh on a fresh box installs v0.6.0 cleanly

🤖 Generated with Claude Code