feat(project): render create results as JSON and truncate task titles

[AlexanderRichey]

Follow-ups to the live progress UI now on refactor (#2163, #2174).

• --json output for project create: the success message is rendered as JSON on stdout ({"message": "Created project ..."}), and a create failure is rendered as {"error": ...} before the error is rethrown unchanged for exit-code handling — matching what build and deploy already do.
• TaskList title truncation: a title longer than the terminal is truncated with … instead of wrapping. Left to wrap, the flexbox layout shrinks the 1-character ✓/✕/spinner glyph column to nothing, so the step's status disappeared.
• Line-splitter coverage at the manager level: a test that subprocess chunks splitting a line mid-word ("found 0 vulnerabilit" + "ies\n") still arrive as whole-line output events.

Test plan

• bun test (full suite passes; the one flake, src/io/watchFile.test.ts debounce timing, passes in isolation and is untouched here)
• bun run typecheck

🤖 Generated with Claude Code

https://claude.ai/code/session_01V2DArb473daWaE6G6B6fSq

[agentcore-devx-automation]

Claude Security Review: no high-confidence findings. (run)

[agentcore-devx-automation]

AgentCore Harness Review

Verdict: Looks good

Focused change with clear intent and good tests:

• TaskList.tsx: The columns - 2 truncation (with Math.max(..., 3) floor for the ellipsis) matches the "glyph + space" prefix for both the spinner and done/error rows. Preserving the || fallback for columns is correct.
• manager.test.ts: The chunked-mid-line runner mock is a nice, precise regression test for line buffering — exactly the right level of test double.
• handlers/project/create/index.ts: JSON success on stdout + human lines on stderr is consistent with the "same driver as build and deploy" comment; error path calls renderJsonError then re-throws so the caller's exit-code handling still fires. The failure test is clever (first create succeeds, second collides on the existing directory) and asserts both the JSON body on stdout and that the error still propagates.

Nothing to change — LGTM.

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 97.13%. Comparing base (16db5b4) to head (af81e1f).

Additional details and impacted files

@@             Coverage Diff              @@
##           refactor    #2184      +/-   ##
============================================
+ Coverage     97.08%   97.13%   +0.04%     
============================================
  Files           536      536              
  Lines         36979    36984       +5     
============================================
+ Hits          35901    35923      +22     
+ Misses         1078     1061      -17     

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[AlexanderRichey]

Dupe