Split single-container Coder template into per-env templates

The old root main.tf tried to switch dev profiles inside one shared
container via a coder_parameter dropdown; the settings-application path
looked for a *.json cache file that never existed (the cache was written
as *.code-profile), so profile settings never actually applied, and VS
Code extensions were copied from extensions/ (which turns out to be
Claude Code plugin bundles, not real VS Code extension packages).

Replace it with one independent Coder template per environment
(templates/default, 3d-printing, cobol, python, ttrpg, web). Each reads
its matching profile-templates/*.code-profile file at template-push time
via file()/jsondecode(), feeds the extension ID list straight into the
code-server module's `extensions` input, and writes the raw settings.json
text via a coder_script - no runtime Gitea zip download needed anymore.

Also add scripts/cli-setup-wizard.sh, hooked into every new interactive
shell until completed, offering to install/log into GitHub Copilot CLI,
Google Antigravity CLI, and Claude Code CLI. VS Code extensions are
deliberately not asked about there since Terraform already handles them.

All six templates verified with `terraform init`/`validate` against the
real coder-server container on octo-winsrv.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

.gitattributes

@@ -0,0 +1,4 @@
+* text=auto eol=lf
+*.sh text eol=lf
+*.tf text eol=lf
+*.code-profile -text