hooks: add explicit 10s timeout to SessionStart hooks

[TotalyNotABotTrustMe]

The SessionStart hook blocks session start (async: false in the Claude Code config) but had no explicit timeout in hooks/hooks.json or hooks/hooks-cursor.json, so it silently relied on each platform's default (600s for Claude Code). If the hook ever hung, that's up to a 10-minute stall on every session start with no explanation.

The hook just reads one file and does string escaping, so it should finish in milliseconds. Set an explicit 10s timeout on both configs so a hang fails fast instead of silently eating minutes.

Refs #1560

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What this fixes

Part of #1560.

The SessionStart hook blocks session start (async: false in the Claude Code config) but had no explicit timeout in hooks/hooks.json or hooks/hooks-cursor.json, so it silently relied on each platform's default (600s for Claude Code). If the hook ever hung, that's up to a 10-minute stall on every session start with no explanation.

The hook just reads one file and does string escaping, so it should finish in milliseconds. Set an explicit 10s timeout on both configs so a hang fails fast instead of silently eating minutes.

What this doesn't cover

#1560 also mentions "descriptions are uniform" and "one skill is large" (writing-skills/SKILL.md is 679 lines vs. the next-largest at 503). The issue body was empty, so I didn't want to guess at what "descriptions are uniform" means — happy to take a pass at the skill-size part separately if useful, or if a maintainer can clarify the other one.

Testing

• Both hooks.json files still parse as valid JSON
• tests/hooks/test-session-start.sh passes