feat(bun): add bun pm

[Ffinnis]

Summary

Adds bun/bunx package manager support across all JS tooling commands. Projects with bun.lockb/bun.lock now automatically use bunx instead of npx for tsc, next, prettier, playwright, prisma, vitest, and lint.

• detect_package_manager(): detects bun.lockb/bun.lock (highest priority)
• package_manager_exec(): routes through bunx for bun projects
• tsc, next, prisma: replaced hardcoded npx fallback with package_manager_exec()
• playwright: added "bun" branch alongside pnpm/yarn/npm
• strip_pm_prefix: recognizes bun prefix in lint args
• Discover rules: bun/bunx patterns, rewrite prefixes for all JS tools
• Error messages updated to mention bun as install option

Changes

• src/utils.rs: bun detection in detect_package_manager(), bunx in package_manager_exec()
• src/tsc_cmd.rs: use package_manager_exec("tsc") instead of hardcoded npx
• src/next_cmd.rs: use package_manager_exec("next") instead of hardcoded npx
• src/prisma_cmd.rs: create_prisma_command() delegates to package_manager_exec()
• src/main.rs: prisma passthrough via package_manager_exec() instead of npx
• src/playwright_cmd.rs: added bun branch to PM match
• src/lint_cmd.rs: added "bun" to strip_pm_prefix
• src/discover/rules.rs: 2 new patterns (bun, bunx), 2 new rules, bunx prefixes in all tool rules
• src/discover/registry.rs: 19 new tests for classify/rewrite
• src/format_cmd.rs, src/prettier_cmd.rs: error messages mention bun

Test plan

• cargo fmt --all --check && cargo clippy --all-targets && cargo test passes
• 19 new bun/bunx tests (classify, rewrite, strip_pm_prefix)
• PATTERNS/RULES alignment test passes (pre-existing)
• 728 total tests, 0 failures

[pszymkowiak]

Hi! Thanks for the contribution! Since March 6, all PRs should target the develop branch instead of master (see CONTRIBUTING.md).

Could you update the base branch? Click Edit at the top right of this PR and change it from master to develop.

Thanks!

[Ffinnis]

#548 implemented in the another PR