fix: keep non-ASCII text readable in merged JSON settings files

[kartsan03]

Description

Two writers that merge Spec Kit entries into a user's existing JSON config call json.dumps without ensure_ascii=False, so every non-ASCII character already in that file comes back as a \uXXXX escape:

• CopilotIntegration._merge_vscode_settings → .vscode/settings.json (Copilot --commands mode)
• events._safe_write_json → the agent hook configs merged by install_integration_events / remove_integration_events (.claude/settings.json, opencode.json, .cursor/hooks.json, .devin/hooks.v1.json, …)

Both files are user-owned and hand-edited (_load_user_json already treats them that way), so running specify init or toggling events mangles text the user wrote. This is the JSON counterpart of #4148, which fixed the same thing for YAML overlay files.

Reproduction on current main, with an existing .vscode/settings.json:

{
    "cSpell.words": ["naïve", "Привіт"]
}

specify init --here --integration copilot --integration-options="--commands" --force rewrites it as:

{
    "cSpell.words": [
        "naïve",
        "Привіт"
    ],

Same for .claude/settings.json (e.g. an env value) when Claude hooks are installed.

The value still parses back identically, so this is not data loss, only legibility of a file the user owns. Both files are already written with encoding="utf-8"; pure-ASCII files produce identical bytes.

Testing

• Tested locally with uv run specify --help

• Ran existing tests with uv sync && uv run pytest

• Tested with a sample project (if applicable)

• New tests, one per writer: test_setup_merge_keeps_non_ascii_vscode_settings_readable (Copilot) and test_merge_keeps_non_ascii_user_settings_readable (Claude hooks merge). Both fail on main and pass with the change; each also checks the value round-trips through json.loads.

• Full suite: 8399 passed, 212 skipped (Linux, Python 3.13)

• uvx ruff@0.15.0 check src tests: clean

• Sample project: the specify init command above, run against main and this branch (output shown above).

AI Disclosure

• I did not use AI assistance for this contribution
• I did use AI assistance (fill in the disclosure below)

AI disclosure: Claude Code (Claude Opus 5.5, xhigh reasoning effort, autonomous agent mode) was used for drafting/refactoring the code change, the regression tests and this description.

[Copilot]

Copilot review overview

🟡 Changes recommended

Both writers can now fail on accepted JSON containing escaped lone surrogates.

Review effort: Balanced
Findings: 2

Open (2)

• Escape lone surrogates before strict UTF-8 config writes · New
• Prevent UnicodeEncodeError when writing escaped lone surrogates · New

What changed in this PR

Preserves readable non-ASCII text when merging user-owned JSON settings.

Changes:

• Disables ASCII escaping in both JSON writers.
• Adds regression coverage for Copilot and event configuration merges.

File	Description
src/​specify_cli/​integrations/​copilot/​__init__.py	Preserves Unicode in VS Code settings.
src/​specify_cli/​events/​__init__.py	Preserves Unicode in event configurations.
tests/​integrations/​test_integration_copilot.py	Tests readable Unicode in VS Code settings.
tests/​specify_cli/​events/​test_events.py	Tests readable Unicode in Claude settings.

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[kartsan03]

Addressed the Copilot review in 4d6eec2. Both writers now pass errors="backslashreplace", so an escaped lone surrogate from the user's file ("\ud800") is written back as its \uXXXX escape instead of raising UnicodeEncodeError; all other text stays readable. Added one regression test per writer; both fail on f2cc31a and pass now. tests/integrations, tests/specify_cli/events, tests/test_merge.py: 2720 passed; ruff clean.

Drafted on behalf of @kartsan03 by Claude Code (model: Claude Opus 5.5, autonomous); code, tests and this comment AI-drafted.

[mnriem]

Please address Copilot feedback

[kartsan03]

@mnriem Both Copilot findings are addressed in 4d6eec2 (summary above), and the two threads are now outdated. Could you re-run the Copilot review when you get a chance?

Drafted on behalf of @kartsan03 by Claude Code (model: Claude Opus 5.5, autonomous); comment AI-drafted.

[Copilot]

Copilot review overview

🟢 Approval recommended

The focused changes preserve valid JSON behavior and include positive and edge-case regression coverage.

Review effort: Balanced
Findings: None

Resolved since last review (2)

• Prevent UnicodeEncodeError when writing escaped lone surrogates
• Escape lone surrogates before strict UTF-8 config writes

[mnriem]

Thank you!