feat: graphify support (auto-install /graphify in compatible agents)

[thecodeassassin]

Adds graphify support, modeled on RTK: a global Settings.Graphify toggle that, when enabled, auto-installs the /graphify knowledge-graph skill into compatible agents — and removes it when disabled.

How it works

• Toggle: Settings.Graphify (config + setup-wizard checkbox "Graphify knowledge graph").
• CLI install (build-time, like RTK): --build-arg INSTALL_GRAPHIFY → Dockerfile.base installs the graphifyy pip package (CLI graphify) globally. Toggling requires a rebuild (same model as RTK; confirmed acceptable).
• Per-agent skill registration (runtime): run.go passes -e EXITBOX_GRAPHIFY=true. New entrypoint setup_graphify runs after apply_active_workspace_links/link_skills:
  • enabled → graphify install --platform <agent> (registers /graphify into the agent's persisted skill dir).
  • disabled → removes the …/skills/graphify/ dir (file-based, so it works after a rebuild drops the CLI).

Compatible agents

claude, codex, opencode, copilot, pi — graphify's skill destination matches ExitBox's config layout for these (verified against graphify's _PLATFORM_CONFIG).

Excluded (intentionally, with reason):

• qwen — graphify has no Qwen platform (confirmed with you).
• kimi — graphify's kimi platform writes ~/.kimi/, but ExitBox's Kimi Code uses ~/.kimi-code/ (skill would never be read).
• cursor — graphify's cursor install is project-scoped (.cursor/ rules in the repo), not a global skill.

Tests

• setup_graphify entrypoint test: install for a compatible agent, removal when disabled, skip for an incompatible agent.
• go build, go test ./..., go vet, golangci-lint green; entrypoint suite 112 pass / 2 pre-existing failures (codex session-storage env leak, unrelated).

Note: build-time + entrypoint changes require an image rebuild to take effect.

[github-actions]

Merging this branch will not change overall coverage

Impacted Packages	Coverage Δ	🤖
github.com/Cloud-Exit/ExitBox/cmd	0.00% (ø)
github.com/Cloud-Exit/ExitBox/internal/config	0.00% (ø)
github.com/Cloud-Exit/ExitBox/internal/image	0.00% (ø)
github.com/Cloud-Exit/ExitBox/internal/run	0.00% (ø)
github.com/Cloud-Exit/ExitBox/internal/wizard	0.00% (ø)

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Coverage by file

Changed files (no unit tests)

Changed File	Coverage Δ	Total	Covered	Missed	🤖
github.com/Cloud-Exit/ExitBox/cmd/run.go	0.00% (ø)	0	0	0
github.com/Cloud-Exit/ExitBox/internal/config/defaults.go	0.00% (ø)	0	0	0
github.com/Cloud-Exit/ExitBox/internal/config/types.go	0.00% (ø)	0	0	0
github.com/Cloud-Exit/ExitBox/internal/image/base.go	0.00% (ø)	0	0	0
github.com/Cloud-Exit/ExitBox/internal/run/run.go	0.00% (ø)	0	0	0
github.com/Cloud-Exit/ExitBox/internal/wizard/tui.go	0.00% (ø)	0	0	0
github.com/Cloud-Exit/ExitBox/internal/wizard/wizard.go	0.00% (ø)	0	0	0

Please note that the "Total", "Covered", and "Missed" counts above refer to code statements instead of lines of code. The value in brackets refers to the test coverage of that file in the old version of the code.