chore: remove OpenCode and oh-my-opencode (install + all references)

[MrChrisRodriguez]

Summary

OpenCode is no longer a provider this template ships. This removes its installation, committed config, devcontainer wiring, dependency, and docs. Historical CHANGES.md entries mentioning OpenCode are left intact (accurate history); a new removal entry documents the change.

Deleted

• .devcontainer/on-create/setup-opencode.sh + setup-oh-my-opencode.sh (installer scripts)
• .opencode/ config dir (commands, plugins/graphify.js, skills, opencode.json, oh-my-opencode.jsonc)
• opencode.jsonc (repo root)

Edited — wiring

• on-create.sh — drop the two optional …setup-opencode.sh/setup-oh-my-opencode.sh calls; clean ordering + set -e comments
• devcontainer.json — remove the ${localEnv:HOME}/.local/share/opencode → /mnt/opencode-mount bind mount; OCTO_ALLOWED_PROVIDERS → "claude codex gemini"
• setup-claude-octopus.sh — delete the "OpenCode (skills only, via symlink)" block; reword clone/shared-symlink comments
• setup-graphify.sh — drop the .opencode/plugins/graphify.js example from a comment
• setup-openspec.sh — openspec init --tools now claude,codex,cursor
• secrets.example — OPENAI_API_KEY comment now references the Codex CLI
• init-host.sh — remove mkdir -p "$HOME/.local/share/opencode"
• .gitignore — remove **/opencode/auth.json
• AUTH-PERSISTENCE.md — "this repo allows" now lists three CLIs
• package.json — remove opencode-ai from catalog + devDependencies; bun.lock refreshed (1 pkg removed)

Docs

• README.md — remove the mkdir step, the "Authenticate Opencode" auth step (remaining steps renumbered), the Opencode + oh-my-opencode AI-tools entries, and the Context7 MCP line mention
• AGENTS.md — drop "Opencode" from the AI-coding-tools list
• CHANGES.md — append one removal entry (history preserved)

Regenerated

• graphify knowledge graph (graphify update ., AST-only — 922 nodes)

Deliberate keep

AUTH-PERSISTENCE.md still lists opencode in the set of provider names Octopus itself recognizes — that documents the third-party tool's capabilities, not our install, so removing it would make the doc inaccurate.

Verification

grep -rni opencode . \
  --exclude-dir=.git --exclude-dir=node_modules --exclude-dir=graphify-out \
  --exclude=bun.lock --exclude=build-log.log --exclude=CHANGES.md
# only AUTH-PERSISTENCE.md (Octopus-recognized provider list) matches
bun -e 'JSON.parse(require("fs").readFileSync("package.json","utf8"))'   # package.json valid

🤖 Generated with Claude Code