feat(cli): scriptable output, shell completion, and CLI refactor

[Remeic]

Summary

Senior-polish pass that builds on the already-solid foundation (100% coverage + 100% mutation, multi-OS CI, release automation). Focus: scriptability, CLI craft, and removing duplication — plus docs that surface the genuinely sophisticated transactional design.

Changes

Refactor — refactor(cli)

• src/lib/errors.ts — shared formatError (was duplicated in profile-store.ts + profile-config-copy.ts)
• src/lib/ui.ts — central output/colors/icons on node:util styleText; NO_COLOR / non-TTY aware (clean strings in pipes, color in a terminal)
• src/lib/run-action.ts — uniform CLI error handling (✗ message + exit 1); removes ~9 duplicated catch blocks and fixes list which previously had none (raw stack trace instead of clean error)

Features — feat(cli)

• ccm list --json / ccm status --json — machine-readable output for scripting/piping; shared projection in profile-view.ts (emits null, not the — placeholder)
• ccm completion <bash|zsh|fish> — completion script with the command list derived from the live registry, so it never drifts as commands are added

Docs — docs

• ARCHITECTURE.md — state reconciliation, the transactional stage→mutate→finalize + rollback protocol, the testability DI seam, and why error handling lives in runAction not index.ts
• CLAUDE.md, .editorconfig, README (--json + completion sections), CONTRIBUTING link

Quality gates

• ✅ Lint (Biome) clean
• ✅ Build (tsup)
• ✅ 365 tests pass (was 326)
• ✅ Coverage 100% (statements / branches / functions / lines)
• ✅ Mutation (Stryker) 100.00%, 0 survivors — every new lib/command file added to mutate[]; list.ts/status.ts newly added to the mutate set and brought to 100%

Notes

• Zero new runtime dependencies — color via node:util styleText, completion hand-derived from program.commands.
• Open questions resolved with defaults: CLAUDE.md only (no AGENTS.md), flat-array JSON shape, static command-name completion.

Verify

ccm list --json | jq '.[] | select(.loggedIn) | .name'
ccm completion zsh
NO_COLOR=1 ccm status   # no ANSI escapes

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 100.00%. Comparing base (7bd68d5) to head (c57743c).

Additional details and impacted files

@@            Coverage Diff            @@
##              main       #51   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files           19        25    +6     
  Lines          554       585   +31     
  Branches       137       135    -2     
=========================================
+ Hits           554       585   +31     

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